Polyester resin and catalyst for polyester production, process for producing polyester resin with the catalyst, polyester resin obtained with the catalyst, and hollow molded container comprising the polyester resins

ABSTRACT

The object of the present invention is to provide a high quality polyester resin having high productivity, stability and safety, a catalyst for polyester production with high catalytic activity, a method for producing the polyester resin with the catalyst, a polyester resin obtained with the catalyst, and a hollow molded container having the polyester resin. The polyester resin of the present invention satisfies specific parameters regarding polymerizability, stability, and metal content. The catalyst for polyester production satisfies specific parameters. The catalyst particularly preferably has: (a) a solid titanium-containing compound which has a maximum solubility in ethylene glycol of 1,000 ppm or more in terms of converted titanium amount when dissolved in ethylene glycol with heating at 150° C., and which has titanium, oxygen, carbon, and hydrogen, and optionally an alkali metal, and has a Ti—O—C bond; and (b) an alkali metal compound, the molar ratio of the alkali metal atoms to the titanium atom in the catalyst being in the range of 20/1 to 0.1/1.

TECHNICAL FIELD

The present invention relates to a polyester resin and a catalyst forpolyester production, a method for producing a polyester resin with thecatalyst, a polyester resin obtained with the catalyst, and a hollowmolded container comprising the polyester resin. More specifically, thepresent invention relates to a polyester resin which satisfies specificparameters, a catalyst for polyester production which allowspolycondensation of aromatic dicarboxylic acids and aliphatic diols at ahigh polymerization rate, a method for producing a polyester resin withthe catalyst, a polyester resin obtained with the catalyst and a hollowmolded container comprising the polyester resin.

BACKGROUND ART

A polyester resin, for example, polyethylene terephthalate is excellentin mechanical strength, heat resistance, transparency and gas barrierproperty, and suitably used as a material for containers used to packagebeverages such as juice, refresh beverage and carbonated drinks and thelike, as well as a material for films, sheets and fibers.

Such polyester resin is usually prepared using dicarboxylic acid such asterephthalic acid and the like, and aliphatic diol such as ethyleneglycol and the like. Specifically, first, aromatic dicarboxylic acidsand aliphatic diols are subjected to esterification to form a lowmolecular condensate (ester oligomer), then the low molecular condensateis subjected to deglycol reaction (liquid polycondensation) underpresence of polycondensation catalyst to attain a high molecular weightof the polymer. In addition, the polyester resin which is used as amaterial for a beverage packaging container, is usually prepared bycarrying out solid polycondensation followed by elevating the molecularweight with volatizing and removing low molecular side products such asacetaldehyde which adversely affects the taste of the beverage. Thispolyester resin is then provided to a molding machine such as aninjection molding machine to form a preform for a hollow molded body.Thereafter, the preform is inserted to a mold having a certain shape forstretch blow molding, or further heat-treated (heat set) to form ahollow molded container.

In such method for producing the polyester resin, an antimony compound,a germanium compound and the like are conventionally used as apolycondensation catalyst.

However, the polyethylene terephthalate produced by using antimonycompound as a catalyst is inferior to that produced by using a germaniumcompound as catalyst in respect to transparency and heat resistance. Onthe other hand, the high cost of germanium compound increases productioncost of the polyester resin. To reduce the catalyst cost, there needs aprocess such as recovering and recycling the germanium compoundvolatized in the polycondensation.

In addition, since polymerization activity per metal weight of theantimony compound or germanium compound and the like is not high, theuse of relatively high concentration of the antimony compound orgermanium compound or the like is needed to produce a polyester resin ata rate to satisfy industrial production. As a result, the polyesterresin produced by using these compounds usually has 50 ppm to 300 ppm ofantimony or germanium and the like as a metal atom.

In recent years, in view of the impact the industrial products have onthe earth environment from their production to disposal, it is stronglyrequired to reduce their adverse effect should be reduced. For example,when considering the life cycle of the polyester products as a beveragepackaging container, it is important to minimize metal, in particular,heavy metal from being flown out from the polyester container to thebeverage. Hence, it is preferred that the metal content in the polyesterresin is low. Further, a low metal content is also preferred in burningup the polyester resin after use since the metal is a source of ashwhich needs additional treatment. In addition, the low metal content isalso preferred in depolymerization of the polyester resin to recover andrecycle the monomers after use since the metal may be a source of theimpurities in the recovered monomers. As described above, reducing thecontent of the metal, in particular, heavy metal contained in thepolyester resin has significant meanings.

By the way, titanium is known as an atom to have activity to promote thepolycondensation reaction of the low molecular condensate. Titaniumalkoxide, titanium tetrachloride, titanyl oxalate, orthotitanic acid andthe like are well-known as a polycondensation catalyst. Manyinvestigations have been conducted to use such titanium compounds as apolycondensation catalyst. Such titanium compounds have highpolymerization activity per metal weight, and are catalysts which mayreduce the amount of metal to be used, considering only the aspect ofthe production rate of the polyester resin. In other words, the titaniumcompounds may be used usually in an amount of several ppm to 50 ppm interms of converted titanium atom in producing the polyester resin usingthese compounds.

Although these titanium compounds have the high polycondensationactivity per metal weight, they have a strong tendency to causeundesirable polyester decomposition reaction, and cause the resinquality to be deteriorated by coloring the resin in the polycondensationprocess by producing the side products having low molecular compounds orby decreasing the molecular weight and the like in the melt moldingprocess.

As a result, the polyester resin produced by using these titaniumcompounds as a polycondensation catalyst has low stability, andacetaldehyde produced by thermal decomposition at the time of meltmolding and decrease of the molecular weight, are more prevalent thanthose of the polyester resin produced by using the conventional antimonycompounds or germanium compounds and the like as a polycondensationcatalyst. Therefore, at present, the problems still remain in using thepolyester resin produced by using the titanium compounds as apolycondensation catalyst, as a material for a beverage packagingcontainer.

On the other hand, if the amount of the above-described titaniumcompounds is reduced so as to decrease the deterioration of the resinquality caused by thermal decomposition at the time of melt molding thepolyester resin, the polycondensation rate of the polyester resinbecomes lower than that of the polyester resin produced by using theconventional antimony compound or germanium compound and the like as apolycondensation catalyst. As a result, longer polymerization time orhigher polymerization temperature is required, which increases theproduction cost of the polyester resin.

DISCLOSURE OF INVENTION

In light of the above-described technical background, the presentinventors have investigated eagerly on the polyester resin and, havefound a polyester resin which satisfies the specific polymerizabilityparameter, and further the specific stability parameter and the metalcontent parameter.

The present inventors have further found that aromatic dicarboxylic acidand aliphatic diol can be subjected to polycondensation at a highproduction rate despite the presence of low metal amount, and that thestability of the produced polyester resin can be improved, with the useof

(1) a catalyst for polyester production comprising a solidtitanium-containing compound which comprises titanium, oxygen, carbon,and hydrogen, and optionally alkali metal, and has a Ti—O—C bond, andfurther the maximum solubility in ethylene glycol is more than aspecific amount in terms of converted titanium atom; and alkali metalcompound, the molar ratio of the alkali metal atoms to the titanium atomin the catalyst (alkali metal/titanium) being in a specific range; or

(2) a catalyst for polyester production comprising a solidtitanium-containing compound which comprises titanium, oxygen, carbon,and hydrogen, and alkali metal, and has a Ti—O—C bond, and further themaximum solubility in ethylene glycol is more than a specific amount interms of converted titanium atom, the molar ratio of the alkali metalatoms to the titanium atom in the catalyst being in a specific range.

As a result, the present inventors have achieved the present invention.

According to the present invention, a polyester resin and a catalyst forpolyester production, a method for producing a polyester resin with thecatalyst, a polyester resin obtained with the catalyst, and a hollowmolded container comprising the polyester resin, as follows are providedto accomplish the above-described object of the present invention.

(1) A polyester resin of which the polymerizability parameter satisfiesthe following formula (A-1), the stability parameter satisfies thefollowing formula (B-1), and the metal content parameter furthersatisfies the following formula (C-1):V _(ssp)≧0.025(dl/g·h)   (A-1)

(wherein V_(ssp) is calculated from the intrinsic viscosity of polyesterresin and from the intrinsic viscosity of polyester resin after solidpolycondensation of the polyester resin at 220° C. under nitrogenatmosphere for any hours between 2 hours to 12 hours, by the followingcalculation formula:V _(ssp)=([IV] ₁ −[IV] ₀)/T

[IV]₀ and [IV]₁ represent intrinsic viscosities (dl/g)before and afterthe solid polycondensation, respectively, and T represents solidpolycondensation time (h).)ΔAA≦7.0 (ppm)   (B-1)

(wherein ΔAA is calculated from the acetaldehyde amount containedoriginally in the polyester resin and from the acetaldehyde amountcontained in a preform obtained by molding the polyester resin with aninjection molding machine at a cylinder temperature of 265 to 275° C.for 26±1 seconds of a molding cycle, by the following calculationformula:ΔAA=[AA] ₁ −[AA] ₀

[AA]₀ and [AA]₁ represent acetaldehyde contents (ppm by weight) beforeand after the molding, respectively.)M≦50 (ppm)   (C-1)

(wherein M represents the total amount (ppm by weight) of the metalatoms contained in the polyester resin.).

(2) The polyester resin as described in (1), wherein thepolycondensation time further satisfies the following formula (A-2):T≦8 (h)   (A-2)

(wherein T represents solid polycondensation time (h) required forelevating the molecular weight of the polyester resin to attain anintrinsic viscosity of 0.84 dl/g by carrying out solid polycondensationof the polyester resin having an intrinsic viscosity of 0.64 dl/g at220° C. under nitrogen atmosphere.).

(3) The polyester resin as described in (1) or (2), wherein the metalcontent parameter further satisfies the following formula (C-2):HM≦2 (ppm)   (C-2)

(wherein HM represents the total amount (ppm by weight) of the heavymetal atoms contained in the polyester resin.).

(4) A catalyst for polyester production comprising

(a) a solid titanium-containing compound which comprises titanium,oxygen, carbon, and hydrogen, and optionally alkali metal, and has aTi—O—C bond, and further the maximum solubility in ethylene glycol whendissolved in the ethylene glycol at 150° C. is 1,000 ppm or more interms of converted titanium atom, and

(b) alkali metal compound; or

(a) a solid titanium-containing compound which comprises titanium,oxygen, carbon, and hydrogen, and further alkali metal, and has a Ti—O—Cbond, and further the maximum solubility in ethylene glycol whendissolved in the ethylene glycol at 150° C. is 1,000 ppm or more interms of converted titanium atom,

the molar ratio of the alkali metal atoms to the titanium atom (alkalimetal/titanium) in the catalyst being in the range of 20/1 to 0.1/1.

(5) The catalyst for polyester production as described in (4), whereinthe solid titanium-containing compound (a) further contains alkali metalin addition to titanium, oxygen, carbon and hydrogen.

(6) A catalyst for polyester production comprising a solidtitanium-containing compound (a) which comprises titanium, oxygen,carbon, hydrogen, and alkali metal, and has a Ti—O—C bond, and furtherthe maximum solubility in ethylene glycol when dissolved in the ethyleneglycol under heating at 150° C. is 1,000 ppm or more in terms ofconverted titanium atom, the molar ratio of the alkali metal atoms tothe titanium atom being in the range of 20/1 to 0.1/1.

(7) The catalyst for polyester production as described in any one of (4)to (6), wherein the titanium atom content in the solidtitanium-containing compound (a) is 5 to 50% by weight, the carbon atomcontent is 1 to 35% by weight, and the weight ratio (Ti/C) of titaniumatom and carbon atom is in the range of 50 to 1.

(8) The catalyst for polyester production as described in any one of (4)to (7), wherein the solid titanium-containing compound (a) contains atleast one kind of element selected from the group consisting ofberyllium, magnesium, calcium, strontium, barium, scandium, yttrium,lanthanum, zirconium, hafnium, vanadium, niobium, tantalum, chrome,molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium,nickel, palladium, copper, zinc, boron, aluminum, gallium, silicon,germanium, tin, antimony and phosphorus in addition to titanium, oxygen,carbon, hydrogen and alkali metal.

(9) The catalyst for polyester production as described in any one of (4)to (8), wherein the solid titanium-containing compound (a) is a productof contact between hydrolysate of titanium halide or hydrolysate oftitanium alkoxide, and polyol.

(10) A catalyst for polyester production comprising

(I) the catalyst for polyester production as described in any one of (4)to (9), and

(II) a compound of at least one kind of element selected from the groupconsisting of-beryllium, magnesium, calcium, strontium, barium, boron,aluminum, gallium, manganese, cobalt, zinc, germanium, antimony andphosphorus.

(11) The catalyst for polyester production as described in any one of(4) to (10), wherein the solid titanium-containing compound (a) is atitanium-containing solution in which the solid titanium-containingcompound (a) is dissolved in ethylene glycol-containing solution (c) inan amount of 500 to 100,000 ppm in terms of converted titanium atom.

(12) The catalyst for polyester production as described in (11), whereinthe titanium-containing solution is obtained by adding the alkali metalcompound (b) when the solid titanium-containing compound (a) isdissolved in the ethylene glycol-containing solution (c).

(13) The catalyst for polyester production as described in (11) or (12),wherein the titanium-containing solution contains a solubilizing aid inthe range of 1 to 50% by weight, relative to the ethyleneglycol-containing solution (c).

(14) The catalyst for polyester production as described in (13), whereinthe solubilizing aid is glycerin or trimethylol propane.

(15) The catalyst for polyester production as described in (13) or (14),wherein the water content of the titanium-containing solution is in therange of 0.05 to 15.0% by weight.

(16) The catalyst for polyester production as described in any one of(4) to (15), substantially comprising no antimony compound and germaniumcompound.

(17) A method for producing a polyester resin, wherein aromaticdicarboxylic acid or an ester-forming derivative thereof and aliphaticdiol or an ester-forming derivative thereof are subjected topolycondensation to produce the polyester resin under presence of thecatalyst for polyester production as described in any one of (4) to(16).

(18) A polyester resin produced by polycondensation of aromaticdicarboxylic acid or an ester-forming derivative thereof and aliphaticdiol or an ester-forming derivative thereof under presence of thecatalyst for polyester production as described in any one of (4) to(16).

(19) The polyester resin as described in (18), made by solidpolycondensation having an intrinsic viscosity of 0.60 dl/g or more.

(20) A hollow molded container comprising the polyester resin asdescribed in (18) or (19).

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the polyester resin, the catalyst for polyester production,the method for, producing the polyester resin with the catalyst, thepolyester resin obtained with the catalyst and the hollow moldedcontainer comprising the polyester resin according to the presentinvention will be explained.

Polyester Resin

In the polyester resin of the present invention, the polymerizabilityparameter satisfies the following formula (A-1), the stability parametersatisfies the following formula (B-1), and the metal content parameterfurther satisfies the following formula (C-1):V _(ssp)≧0.025 (dl/g·h)   (A-1)

(wherein V_(ssp) is calculated from the intrinsic viscosity of thepolyester resin, and from the intrinsic viscosity of a polyester resinobtained by solid polycondensation of this polyester resin at 220° C.under nitrogen atmosphere for any hours between 2 hours and 12 hours, bythe following calculation formula:V _(ssp)=([IV] ₁ −[IV] ₀)/T

wherein [IV]₀ and [IV]1 represent intrinsic viscosities (dl/g) beforeand after the solid polycondensation, respectively, and T representssolid polycondensation time (h).);ΔAA≦7.0 (ppm)   (B-1)

(wherein ΔAA is calculated from the acetaldehyde amount containedoriginally in the polyester resin, and from the acetaldehyde amountcontained in the preform obtained by molding this polyester resin withan injection molding machine at a cylinder temperature of 265 to 275° C.for 26±1 seconds of a molding cycle, by the following calculationformula:ΔAA=[AA] ₁ −[AA] ₀

wherein [AA]₀ and [AA]₁ represent acetaldehyde contents (ppm by weight)before and after the molding, respectively.)M≦50 (ppm)   (C-1)

(wherein M represents the total amount (ppm by weight) of the metalatoms contained in the polyester resin.).

V_(ssp), the polymerizability parameter of the polyester resin asdescribed in Formula (A-1) herein, indicates the increasing rate ofintrinsic viscosity per hour when the polyester resin is subjected tosolid polycondensation at 220° C. under nitrogen atmosphere for anyhours between 2 hours and 12 hours. According to the experiments by thepresent inventors, if the solid polycondensation time is less than 2hours, the temperature or atmosphere in the reaction system is notstable. In addition, if solid polycondensation time is more than 12hours, the increasing rate of intrinsic viscosity is saturated. Ineither case, linear correlation between the intrinsic viscosity and thesolid polycondensation time is lost. However, if the solidpolycondensation time is within the range of 2 hours to 12 hours,V_(ssp) can be considered as nearly constant.

Formula (A-1) indicates that the polyester resin according to thepresent invention has comparable or higher polymerizability as comparedwith the polyester resin produced by using the antimony compound orgermanium compound that is currently used in the industry. In otherwords, the polyester resin according to the present invention can beproduced at a comparable or higher production rate as compared with thatof the polyester resin produced by using the existing antimony compoundor germanium compound.

ΔAA, the stability parameter of the polyester resin as described inFormula (B-1), indicates the increased amount of the acetaldehyde whenthe polyester resin in an injection molding machine is molded at acylinder temperature of 265 to 275° C. of for 26±1 seconds of a moldingcycle to obtain a preform. Formula (B-1) indicates that the polyesterresin according to the present invention has comparable or lessincreased amount of acetaldehyde as compared with the polyester resinproduced by using the antimony compound or germanium compound that iscurrently used in the industry. The acetaldehyde is produced bydecomposition of the polyester resin by heating at the time of preformmolding and by the action of the polycondensation catalyst contained inthe polyester resin. The acetaldehyde is the cause that gives beveragesoff-taste and off-odor when the polyester resin is used for a beveragecontainer. In other words, by using the polyester resin according to thepresent invention, a beverage packaging container can be produced in acomparable or better quality as compared with that obtained by using theexisting antimony compound or germanium compound.

M, the metal content parameter of the polyester resin as described inFormula (C-1), indicates the total amount of the metal atoms containedin the polyester resin. As described in the BACKGROUND ART of theinvention, it is desirable to reduce the metal content in the polyesterresin to minimize its adverse effect on the earth environment. Inaddition, the polyester resin produced by using the antimony compound orgermanium compound that is currently used in the industry as describedalso in the BACKGROUND ART of invention, contains usually 50 to 300 ppmof the metal atoms.

Formula (C-1) indicates that the polyester resin according to thepresent invention has a comparable or less metal content as comparedwith the polyester resin produced by using the antimony compound orgermanium compound that is currently used in the industry. In otherwords, it indicates that the polyester resin according to the presentinvention has comparable or better environment safety as compared withthe polyester resin produced by using the existing antimony compound orgermanium compound.

In the polyester resin according to the present invention, thepolycondensation time preferably further satisfies the following formula(A-2):T≦8 (h)   (A-2)

(wherein T represents solid polycondensation time (h) required forelevating the molecular weight of the polyester resin to the intrinsicviscosity of 0.84 dl/g by carrying out solid polycondensation of thepolyester resin having an intrinsic viscosity of 0.64 dl/g at 220° C.under nitrogen atmosphere.)

In the polyester resin according to the present invention, the metalcontent parameter of the produced polyester resin preferably furthersatisfies the following formula (C-2):HM≦2 (ppm)   (C-2)

(wherein HM represents the total amount (ppm by weight) of the heavymetal atoms contained in the polyester resin.

The heavy metal herein indicates the elements from Group III exceptradium, scandium and yttrium, the elements from Group IV excepttitanium, all the elements from Groups V to XII, the elements from GroupXIII except boron and aluminum, the elements from Group XIV exceptcarbon and silicon, the elements from Group XV except nitrogen,phosphorus and arsenic, and the elements from Group XVI except oxygen,sulfur and selenium as classified in ‘Metal Toxicology’ edited byKenzaburo Tsuchiya and published by Ishiyaku Publisher, (1983).

Catalyst for Polyester Production

The catalyst for polyester production according to the present inventioncomprises

(a) a solid titanium-containing compound which comprises titanium,oxygen, carbon hydrogen, and alkali metal, and has a Ti—O—C bond, andfurther the maximum solubility in ethylene glycol when dissolved in theethylene glycol at 150° C. is 1,000 ppm or more in terms of convertedtitanium atom, or

(a) a solid titanium-containing compound which comprises titanium,oxygen, carbon, and hydrogen, and optionally alkali metal, and has aTi—O—C bond, and further the maximum solubility in ethylene glycol whendissolved in the ethylene glycol at 150° C. is 1,000 ppm or more interms of converted titanium atom; and

(b) alkali metal compound.

(a) Solid Titanium-Containing Compound

The solid titanium-containing compound (a) which forms the catalyst forpolyester production according to the present invention comprisestitanium, oxygen, carbon, and hydrogen, and optionally alkali metal, andhas a Ti—O—C bond.

The alkali metal herein includes Li, Na, K, Rb and Cs.

Solid titanium-containing compound (a) preferably contains titanium inan amount of 5 to 50% by weight, and preferably (5 to 40)% by weight,oxygen in an amount of (35 to 75)% by weight, and preferably (40 to 60)%by weight, carbon in an amount of 1 to 35% by weight, and preferably (5to 25)% by weight, and hydrogen in an amount of (1 to 10)% by weight,and preferably (1 to 6)% by weight.

If the solid titanium-containing compound (a) contains titanium, oxygen,carbon and hydrogen in the above range, the solid titanium-containingcompound exhibits good solubility.

The alkali metal is preferably contained in an amount that the molarratio of the alkali metal atoms to the titanium atom (alkalimetal/titanium) in the solid titanium-containing compound (a) is in therange of 20/1 to 0.1/1, and preferably 10/1 to 0.1/1.

If the molar ratio of the alkali metal atoms to the titanium atom in thesolid titanium-containing compound (a) is in the above range, a highquality polyester resin can be produced with high polymerizationactivity and improved solubility. If the alkali metal atom content isless than the above range, the effect to the activity and quality bycontaining the alkali metal may not be obtained sufficiently. Inaddition, if the alkali metal atom content is more than the above range,to the contrary the activity may decrease.

In addition, if the solid titanium-containing compound (a) has Ti—O—Cbond, the solubility of the solid titanium-containing compound ispreferably good.

In the solid titanium-containing compound (a), the weight ratio (Ti/C)of titanium atom and carbon atom is in the range of 50 to 1, andpreferably 25 to 2.

If the weight ratio of titanium atom and carbon atom is within the aboverange, it has the following effects. If the weight ratio is less thanthe upper limit of this range, carbon can reach solid though carbon isderived from specific liquid alcohol. In addition, if the weight ratiois more than the lower limit of this range, the maximum solubility inethylene glycol becomes at least 1000 ppm.

The titanium content in the solid titanium-containing compound (a) canbe measured, for example, by ICP analysis, and the content of otherelements can be measured, for example, by element analysis.

In addition, Ti—O—C bond in the solid titanium-containing compound (a),can be confirmed by element analysis, EXAFS analysis and ¹³C-NMRanalysis.

Maximum solubility of the solid titanium-containing compound in ethyleneglycol when the solid titanium-containing compound is dissolved inethylene glycol under heating at 150° C., is 1000 ppm or more,preferably 1500 ppm or more, and more preferably 2000 ppm or more interms of converted titanium atom.

If the maximum solubility in ethylene glycol when the solidtitanium-containing compound is dissolved in ethylene glycol underheating at 150° C., is much less than the above range, the amount of thesolvent which is added to the polymerization reactor when the catalystis added to the polymerization reactor, become undesirably excessive andaffects the polymerization, and dissolution becomes difficult.

For the maximum solubility in ethylene glycol of the solidtitanium-containing compound (a), the solid titanium-containing compound(a) is dissolved in 100 g of ethylene glycol which is solvent underheating at 150° C., the transparency of the solution is measured with ahazemeter. The amount exceeding 10% is checked, and from the amount ofthe solid titanium-containing compound at this time, the maximumsolubility is determined.

Mean particle diameter of the solid titanium-containing compound (a) ispreferably 1 to 30 μm, and more preferably 1.5 to 20 μm.

If the mean particle diameter of the solid titanium-containing compound(a) is within the above range, the solubility of the solidtitanium-containing compound is preferably good.

In addition, the degree of crystallization of the solidtitanium-containing compound (a) which is derived from the structure ofanatase-type titanium dioxide and calculated from X ray diffractionpattern having 20 (the angle of diffraction) in the range of 18° to 35°,is preferably 50% or less. If the degree of crystallization is 50% orless, the catalytic activity is excellent, and the solubility of thesolid titanium-containing compound is preferably good.

The solid titanium-containing compound (a) may contain other elementsthan titanium, oxygen, carbon and hydrogen (hereinafter, it may besimply referred to as “other elements”). Such elements include at leastone kind of element selected from the group consisting of beryllium,magnesium, calcium, strontium, barium, scandium, yttrium, lanthanum,zirconium, hafnium, vanadium, niobium, tantalum, chrome, molybdenum,tungsten, manganese, iron, ruthenium, cobalt, rhodium, nickel,palladium, copper, zinc, boron, aluminum, gallium, silicon, germanium,tin, antimony and phosphorus. Among these, magnesium is preferred. Theseother elements may be contained in the solid titanium-containingcompound in combinations of two or more.

In the solid titanium-containing compound (a) containing the otherelements, the molar ratio (M/Ti) of titanium (Ti) and the other elements(M) is in the range of 1/50 to 50/1, preferably 1/40 to 40/1, and morepreferably 1/30 to 30/1.

If the molar ratio of titanium (Ti) in the solid titanium-containingcompound (a) and the other elements (M) is within the above range, thecatalytic activity is excellent, and there is no adverse effect on thesolubility of the solid titanium-containing compound, hence the aboverange is preferred.

The solid titanium-containing compound (a) can be used as atitanium-containing solution by dissolving in the ethyleneglycol-containing solution (c) as described below.

If the solid titanium-containing compound (a) does not contain thealkali metal, it can be used as the catalyst for polyester production incombination with the alkali metal compound (b). If the solidtitanium-containing compound (a) contains the alkali metal, it can beused as the catalyst for polyester production alone or in combinationwith the alkali metal compound (b). In either case, it may be used asthe catalyst for polyester production in combination with the compound(II) which will be described below.

(b) Alkali Metal Compound

The alkali metal compound (b) that forms the catalyst for polyesterproduction according to the present invention is at least one kind ofalkali metal compound selected from the group consisting of simplesubstance of alkali metal, alkali metal hydride, alkali metal hydroxide,alkali metal alkoxide, alkali metal halide, and alkali metal salt ofacid selected from carbonic acid, nitric acid, nitrous acid, sulfuricacid, sulfurous acid, organic sulfonic acid, phosphoric acid,phosphorous acid, hypophosphite, meta-phosphoric acid, polyphosphoricacid, organic phosphonic acid, organic phophinic acid, boric acid,aluminum acid, titanium acid, silic acid, aliphatic acid, aromaticcarboxylic acid, hydroxycarboxylic acid and amino acid.

The simple substance of the alkali metal includes Li, Na, K, Rb and Cs.

The alkali metal hydride includes LiH, NaH, KH, RbH and CsH.

The alkali metal hydroxide includes lithium hydroxide, sodium hydroxide,potassium hydroxide, rubidium hydroxide, cesium hydroxide and the like.

The alkali metal alkoxide compound includes sodium methoxide, sodiumethoxide and the like.

The alkali metal halide includes lithium fluoride, sodium fluoride,potassium fluoride, rubidium fluoride, cesium fluoride, lithiumchloride, sodium chloride, potassium chloride, rubidium chloride, cesiumchloride, lithium bromide, sodium bromide, potassium bromide, rubidiumbromide, cesium bromide, lithium iodide, sodium iodide, potassiumiodide, rubidium iodide, cesium iodide and the like.

The alkali metal salt of acid selected from carbonic acid, nitric acid,nitrous acid, sulfuric acid, sulfurous acid, organic sulfonic acid,phosphoric acid, phosphorous acid, hypophosphite, meta-phosphoric acid,polyphosphoric acid, organic phosphonic acid, organic phophinic acid,boric acid, aluminum acid, titanium acid, silic acid, aliphatic acid,aromatic carboxylic acid, hydroxycarboxylic acid, and amino acidincludes alkali metal salt of aliphatic acid such as sodium acetate,sodium propionate, sodium butyrate, sodium caproate, sodium caprylate,sodium caprate, sodium laurate, sodium myristate, sodium palmitate,sodium stearate and the like; alkali metal salt of hydroxycarboxylicacid such as sodium glycolate, sodium lactate, sodium malate, sodiumtartarate, sodium citrate, sodium gluconate and the like; alkali metalsalt of amino acid such as sodium glutamate, sodium asparaginate and thelike.

Among these alkali metal compounds (b), sodium hydroxide, potassiumhydroxide, sodium methoxide, sodium acetate, sodium stearate and thelike are preferred.

The alkali metal compound (b) may be used alone or in combinations oftwo or more.

Alkali metal compound (b) is preferably used in such an amount that themolar ratio of alkali metal in the alkali metal compound (b), andtitanium in the solid titanium-containing compound (a) or in thetitanium-containing solution (alkali metal/titanium), or the molar ratioof alkali metal in the solid titanium-containing compound (a) and inalkali metal compound (b), and titanium in the solid titanium-containingcompound (a) or in the titanium-containing solution (alkalimetal/titanium) if solid titanium-containing compound (a)contains alkalimetal, is in the range of 20/1 to 0.1/1, and preferably 10/1 to 0.1/1.

If the molar ratio-of titanium atom in the solid titanium-containingcompound (a) or in the titanium-containing solution, and alkali metalatom is within the above range, a high quality polyester resin can beproduced with high polymerization activity and improved solubility. Ifthe content of the alkali metal compound (b) is less than the aboverange, the effect to the activity and quality by containing the alkalimetal may not be obtained sufficiently, while if the content of thealkali metal compound (b) is more than the above range, to the contrarythe activity may decrease.

Compound (II)

The compound (II) is a compound of at least one kind of element selectedfrom the group consisting of beryllium, magnesium, calcium, strontium,barium, boron, aluminum, gallium, manganese, cobalt, zinc, germanium,antimony and phosphorus.

The compound of at least one kind of element selected from the groupconsisting of beryllium, magnesium, calcium, strontium, barium, boron,aluminum, gallium, manganese, cobalt, zinc, germanium, antimony andphosphorus, includes aliphatic acid salt of these elements such asacetate and the like, carbonate, sulfate, nitrate and halide such aschloride and the like of these elements, acetylacetonate salt of theseelements, oxide of these elements and the like, acetate or carbonatebeing preferred.

In addition, the phosphorus compound includes phosphate or phosphite ofat least one kind of metal selected from Group I and Group II of thePeriodic Table of Elements, transition metals of Group IV of thePeriodic Table, zirconium, hafnium and aluminum.

Preferred examples of the compound (II) which is optionally used in thepresent invention, include the following.

The aluminum compounds include aluminum salt of aliphatic acid such asaluminum acetate and the like, aluminum carbonate, aluminum chloride,aluminum acetylacetonate salt and the like. In particular, aluminumacetate or aluminum carbonate is preferred.

The barium compounds include barium salt of aliphatic acid such asbarium acetate and the like, barium carbonate, barium chloride, bariumacetylacetonate salt and the like. In particular, barium acetate orbarium carbonate is preferred.

The cobalt compounds include cobalt salt of aliphatic acid such ascobalt acetate and the like, cobalt carbonate, cobalt chloride, cobaltacetylacetonate salt and the like. In particular, cobalt acetate orcobalt carbonate is preferred.

The magnesium compounds include magnesium salt of aliphatic acid such asmagnesium acetate and the like, magnesium carbonate, magnesium chloride,magnesium acetylacetonate salt and the like. In particular, magnesiumacetate or magnesium carbonate is preferred.

The manganese compounds include manganese salt of aliphatic acid such asmanganese acetate and the like, manganese carbonate, manganese chloride,manganese acetylacetonate salt and the like. In particular, manganeseacetate or manganese carbonate is preferred.

The strontium compounds include strontium salt of aliphatic acid such asstrontium acetate and the like, strontium carbonate, strontium chloride,strontium acetylacetonate salt and the like. In particular, strontiumacetate or strontium carbonate is preferred.

The zinc compounds include zinc salt of aliphatic acid such as zincacetate and the like, zinc carbonate, zinc chloride, zincacetylacetonate salt and the like. In particular, zinc acetate or zinccarbonate is preferred.

The germanium compounds include germanium dioxide, germanium acetate andthe like.

The antimony compounds include antimony dioxide, antimony acetate andthe like.

The phosphates among the phosphorus compounds include lithium phosphate,lithium dihydrophosphate, dilithium hydrophosphate, sodium phosphate,sodium dihydrophosphate, disodium hydrophosphate, potassium phosphate,potassium dihydrophosphate, dipotassium hydrophosphate, strontiumphosphate, strontium dihydrophosphate, distrontium hydrophosphate,zirconium phosphate, barium phosphate, aluminum phosphate, zincphosphate and the like. Among these, in particular sodium phosphate,sodium dihydrophosphate, disodium hydrophosphate, potassium phosphate,potassium dihydrophosphate and dipotassium hydrophosphate are preferablyused.

In addition, the phosphites among the phosphorus compounds includephosphite of at least one kind of metal selected from alkali metal,alkali earth metal, transition metals of Group IV of the Periodic Table,zirconium, hafnium, and aluminum. Specifically, the phosphite includeslithium phosphite, sodium phosphite, potassium phosphite, strontiumphosphite, zirconium phosphite, barium phosphite, aluminum phosphite,zinc phosphite and the like. Among these, in particular sodium phosphateand potassium phosphite are preferably used.

Among these, the compound (II) is preferably a magnesium compound suchas magnesium carbonate, magnesium acetate and the like; a calciumcompound such as calcium carbonate, calcium acetate and the like; or azinc compound such as zinc chloride, zinc acetate and the like.

These compounds (II) can be used alone or in combinations of two ormore.

Such compound (II) is preferably used in an amount that the molar ratio(M/Ti) of titanium (Ti) in the solid titanium-containing compound (a) orin the titanium-containing solution, and metal atom (M) in the compound(II) is in the range of 1/50 to 50/1, preferably 1/40 to 40/1, and morepreferably 1/30 to 30/1. Further, f the phosphorus compound such asphosphate or phosphite and the like is used, it is in terms of convertedmetal atoms contained in the phosphorus compound.

If molar ratio of titanium in the solid titanium-containing compound (a)or in the titanium-containing solution, and metal atom in the compound(II) is within the above range, the effect of improved activity by usingthe compound (II) is obtained sufficiently. If the amount of thecompound (II) is less than the above range, the above effect may not beobtained. In addition, if the amount of the compound (II) is more thanthe above range, the quality of the polyester resin obtained may bedeteriorated.

In addition, if a magnesium compound is used as the compound (II), themagnesium compound is preferably used in an amount that weight ratio(Mg/Ti) of titanium (Ti) in the solid titanium-containing compound (a)or in the titanium-containing solution and Mg atom in the magnesiumcompound is in the range of 0.01 or more, preferably 0.06 to 10, andparticularly preferably 0.06 to 5. If the magnesium compound is usedwithin the above range, transparency of the obtained polyester resin isexcellent.

Process for Producing the Solid Titanium-Containing Compound (a)

The solid titanium-containing compound (a) that forms the catalyst forpolyester production according to the present invention can be obtained,for example, by dehydrating and drying the hydrolysate (h-1) which isobtained by hydrolysis of titanium halide or titanium alkoxide, undercoexistence of polyol.

As the titanium halide, a compound in which at least one bond betweentitanium atom and halogen atom exist(s) in the molecule is used.Specifically, the titanium halide includes titanium tetrahalide such astitanium tetrachloride, titanium tetrabromide, titanium tetraiodide andthe like; titanium trihalide such as titanium trichloride and the like;dihalide such as titanium dichloride and the like and titaniummonohalide. The titanium halide may be diluted to two times or so withwater before use. In addition, titanium alkoxide specifically includestitanium tetrabutoxide, titanium tetraisopropoxide and the like.

A method for hydrolyzing titanium halide or titanium alkoxide is notparticularly limited, but includes, for example, (i) a method to addtitanium halide or titanium alkoxide to water, (ii) a method to addwater to titanium halide or titanium alkoxide, (iii) a method to passgas including vapor of titanium halide or titanium alkoxide throughwater, (iv) a method to pass gas including water vapor through titaniumhalide or titanium alkoxide, (v) a method to contact gas includingtitanium halide or titanium alkoxide with gas including water vapor, andthe like.

The above method for hydrolysis in the present invention not speciallylimited, but in any case, largely excessive water is needed to reactwith titanium halide or titanium alkoxide to conduct hydrolysiscompletely. If hydrolysis does not proceed completely, thus the obtainedhydrolysate is a partial hydrolysate as described in Japanese ExaminedPatent Application Publication No. 51-19477, the activity as apolycondensation catalyst may not be sufficient.

The temperature of hydrolysis is usually 100° C. or lower, andpreferably 0 to 70° C.

Hydrolysate (h-1) of titanium halide or titanium alkoxide obtained bythe hydrolysis is a gel of a hydroxide hydrate composite containing ahydroxide hydrate, which is also referred to as orthotitanic acid, atthis stage. This hydroxide hydrate gel is dehydrated and dried asdescribed below under coexistence of polyol to give a solidtitanium-containing compound (a).

If the titanium halide is subjected to hydrolysis as described above, anacidic solution comprising the hydrolysate (h-1) of titanium halide isobtained, and the pH of this acidic solution is usually approximately 1.

If titanium halide is used as a raw material, the pH of the solutioncomprising the hydrolysate (h-1) is preferably adjusted to 2 to 6 beforedehydrating and drying. A method for adjusting the pH includes a methodto adjust the pH to 2 to 6 with an acid after alkalifying first with abase, a method to adjust the pH of the solution comprising thehydrolysate (h-1) to 2 to 6 directly with a base, and the like.

The method for adjusting the pH to 2 to 6 with an acid after alkalifyingpH first with a base is not specially limited, but includes, forexample, a method in which the pH is first adjusted to 9 to 12 withammonia or sodium hydroxide, potassium hydroxide, sodium carbonate,potassium carbonate and the like, and then, the pH is adjusted to 2 to 6with acetic acid or nitric acid and the like.

In addition, the method to adjust the pH of the solution comprising thehydrolysate (h-1) to 2 to 6 directly with a base is not speciallylimited, but includes, for example, a method in which the pH is adjustedwith ammonia or sodium hydroxide, potassium hydroxide, sodium carbonate,potassium carbonate and the like to pH 2 to 6, in which the titaniumcompound is precipitated.

The temperature in adjusting the pH of the solution comprising thehydrolysate (h-1) is usually 50° C. or lower, and preferably 40° C. orlower.

By adjusting the pH of the solution comprising the hydrolysate (h-1) to2 to 6, a precipitate is produced.

If the pH of the solution comprising the hydrolysate (h-1) is adjustedto 2 to 6 before dehydrating and drying as described above, dehydrationprocess can be carried out in short time. In addition, the level ofnitrogen and the like derived from the base remain low in the catalyst,and the deterioration in activity as a polycondensation catalyst or inquality of the polyester resin produced by the catalyst is reduced.

In addition, the solid titanium-containing compound (a) that forms thecatalyst for polyester production according to the present invention canbe obtained by dehydrating and drying the hydrolysate (h-2) which isobtained by hydrolysis of a mixture of titanium halide or titaniumalkoxide and a compound of the element selected from at least one kindof the other elements or a precursor thereof (hereinafter, it may bereferred to as “compound of the other elements”) under coexistence ofpolyol.

The compound of the other elements includes, for example, hydroxide ofthe above-described elements, and the like. These compounds of the otherelements can be used alone or in combinations of two or more.

The method for hydrolyzing the mixture of titanium halide or titaniumalkoxide and the compounds of the other elements is not particularlylimited, but includes, for example, (i) a method to add titanium halideor titanium alkoxide to water in which the compounds of the otherelements are dissolved or suspended, (ii) a method to add a mixture oftitanium halide or titanium alkoxide and the compounds of the otherelements to water, (iii) a method to add water to a mixture of titaniumhalide or titanium alkoxide and the compounds of the other elements,(iv) a method to add water in which the compounds of the other elementsare dissolved or suspended, to titanium halide or titanium alkoxide, (v)a method to pass gas including vapor of titanium halide or titaniumalkoxide through water in which the compounds of the other elements aredissolved or suspended, (vi) a method to pass gas including vapor oftitanium halide or titanium alkoxide and vapor of the compounds of theother elements through water, (vii) a method to pass gas including watervapor through a mixture of titanium halide or titanium alkoxide and thecompounds of the other elements, (viii) a method to pass gas includingwater vapor and vapor of the compounds of the other elements throughtitanium halide or titanium alkoxide, (ix) a method to contact gasincluding titanium halide or titanium alkoxide and gas including vaporof the compounds of the other elements with gas including water vapor,and the like.

The above method for hydrolysis in the present invention is notspecially limited, but in any case, largely excessive water is needed toreact with a mixture of titanium halide or titanium alkoxide and thecompounds of the other elements to conduct hydrolysis completely. Ifhydrolysis does not proceed completely, thus obtained hydrolysate is apartial hydrolysate, the activity as a polycondensation catalyst may notbe sufficient.

In the hydrolysis, the molar ratio (M/Ti) of titanium (Ti) in titaniumhalide or titanium alkoxide and the other element (M) in the compoundsof the other elements is preferably in the range of 1/50 to 50/1. Inaddition, the temperature of hydrolysis is usually 100° C. or lower, andpreferably, 0 to 70° C.

The hydrolysate (h-2) of the mixture of titanium halide or titaniumalkoxide and the compounds of the other elements, obtained by thehydrolysis, is a gel of hydroxide hydrate, which is also referred to asorthotitanic acid, at this stage. This hydroxide hydrate gel is hydratedand dried as described below under coexistence of polyol to give a solidtitanium-containing compound (a).

The pH of the solution comprising the hydrolysate (h-2) is preferablyadjusted.

A method for adjusting the pH of the solution comprising the hydrolysate(h-2) includes a method same as the method for adjusting the pH of thesolution comprising the hydrolysate (h-1) as described above.

By adjusting the pH of the solution comprising the hydrolysate (h-2) to2 to 6, a precipitate is produced.

If the pH of the solution comprising the hydrolysate (h-2) is adjustedto 2 to 6 before dehydrating and drying as described above, dehydrationprocess can be carried out in short time. In addition, the level ofnitrogen and the like derived from the base remain low in the catalyst,and the deterioration in activity as a polycondensation catalyst or inquality of the polyester resin produced by the catalyst is reduced.

In addition, the solid titanium-containing compound (a) that forms thecatalyst for polyester production according to the present invention,can be obtained by dehydrating and drying a mixture of the hydrolysate(h-1) obtained by hydrolysis of titanium halide or titanium alkoxide,and hydrolysate (h-3) obtained by hydrolysis of the compounds of theother elements or a precursor thereof, under coexistence of polyol.

The compounds of the other elements may be used alone or in combinationsof two or more.

The method for hydrolyzing the compounds of the other elements or aprecursor thereof is not particularly limited, but it may be carriedout, for example, by a method same as the method for preparing thehydrolysate (h-1) except using the compounds of the other elements or aprecursor thereof instead of titanium halide or titanium alkoxide. Byhydrolyzing the compounds of the other elements or a precursor thereof,a solution comprising the hydrolysate (h-3) is obtained.

A mixture of the hydrolysate (h-1) obtained by hydrolysis of titaniumhalide or titanium alkoxide, and hydrolysate (h-3) obtained byhydrolysis of the compounds of the other elements or a precursor thereofcan be prepared by mixing solution of the hydrolysate (h-1) and solutionof the hydrolysate (h-3), which are prepared separately according to theabove methods.

Hydrolysate (h-1) and hydrolysate (h-3) are preferably mixed in such aratio that molar ratio (E/Ti) of titanium (Ti) in hydrolysate (h-1) andthe other elements (M) in hydrolysate (h-3) is in the range of 1/50 to50/1.

This mixture is dehydrated and dried as described below undercoexistence of polyol to give a solid titanium-containing compound (a).

The pH of the solution comprising the hydrolysate (h-1) and hydrolysate(h-3) is preferably adjusted. A method for adjusting the pH of thesolution including hydrolysate (h-1) and hydrolysate (h-3) includes amethod same as the method for adjusting the pH of the solutioncomprising the hydrolysate (h-1) as described above.

By adjusting the pH of the solution comprising the hydrolysate (h-1) andhydrolysate (h-3) to 2 to 6, a precipitate is produced.

If the pH of the solution comprising the hydrolysate (h-1) andhydrolysate (h-3) is adjusted to 2 to 6 before dehydrating and drying asdescribed above, dehydration process can be carried out in short time.In addition, the level of nitrogen and the like derived from the baseremain low in the catalyst, and the deterioration in activity as apolycondensation catalyst or in quality of the polyester resin producedby the catalyst is reduced.

Next, the hydrolysate (h-1), (h-2) or (h-3) is dehydrated and driedbelow under coexistence of polyol to give a solid titanium-containingcompound (a).

The polyol which coexists in dehydrating and drying the hydrolysate(h-1), (h-2) or (h-3) specifically includes di-valent alcohol such asethylene glycol and the like; tri-valent alcohol such as glycerin andthe like. Among these, di-valent alcohol and tri-valent alcohol arepreferred. In particular, ethylene glycol and glycerin are preferred.

A method to make polyol coexist in dehydrating and drying thehydrolysate (h-1), (h-2) or (h-3) includes, for example, a methodcomprising suspending the hydrolysate (h-1), (h-2) or (h-3) in watercontaining 1 to 90% by weight, preferably 2 to 80% by weight, andparticularly preferably 5 to 50% by weight of polyol, followed by dryingthe suspension. In this case, the hydrolysate (h-1), (h-2) or (h-3) isdesirably made to a slurry, and maintained for several minutes toseveral hours.

A method to dry the slurry after the maintenance includes a method todry the slurry after the solid-liquid, a method to use a spray drier asa machine for granulating and drying and the like. A spray drier ispreferably used.

In dehydrating and drying the slurry with a spray drier as a machine forgranulating and drying, a slurry comprising, for example, 0.1 to 15% byweight, and preferably 0.5 to 10% by weight of the hydrolysate (h-1),(h-2) or (h-3) is sprayed under atmosphere of usually 80 to 250° C., andpreferably 120 to 200° C., to give a solid titanium-containing compound(a).

Thus obtained solid titanium-containing compound (a) has particle sizewhich is preferably in the range of 1 to 30 μm.

The solid titanium-containing compound (a) varies depending on the kindor the concentration of the coexisting polyol, a drying method, and theextent of dryness. However, titanium content in the solidtitanium-containing compound (a) is usually in the range of 5 to 50% byweight. If the titanium content is more than 50% by weight, the effectby incorporating polyol scarcely exhibits. In addition, if the titaniumcontent is less than 5% by weight, the amount of the remaining polyol isso high that uniform solid titanium-containing compound (a) cannot beobtained.

If the solid titanium-containing compound (a) contains the otherelements, the molar ratio (M/Ti) of titanium (Ti) in the solidtitanium-containing compound (a) and the other elements M is in therange of 1/50 to 50/1, preferably 1/40 to 40/1, and more preferably 1/30to 30/1.

If the molar ratio (M/Ti) of titanium (Ti) in the solidtitanium-containing compound (a) and the other elements (M) is withinthe above range, the effect of elevation of activity can be sufficientlyobtained by using the other elements. If the amount of the otherelements is less than the above range, the above effect may not beobtained. In addition, if the amount of the other elements is more thanthe above range, the quality of the polyester resin obtained may bedeteriorated.

In the present invention, the titanium content in the solidtitanium-containing compound (a) can be measured for example, by ICPanalysis.

If titanium halide is used in the solid titanium-containing compound (a)as a raw material, the halogen element content is usually 0 to 10,000ppm, and preferably 0 to 100 ppm.

The solid titanium-containing compound (a) may be used as a catalyst bydissolving in ethylene glycol-containing solution (c) including ethyleneglycol. When the solid titanium-containing compound (a) is dissolved inethylene glycol-containing solution (c), it is dissolved preferablyunder presence of a basic compound such as the alkali metal compound (b)and the like.

When the solid titanium-containing compound (a) is dissolved in ethyleneglycol-containing solution (c), it is dissolved preferably underheating. The heating temperature is usually in the range of 100 to 200°C., and preferably 110 to 195° C.

When the alkali metal compound (b) is used, it is used in such an amountthat the molar ratio of alkali metal to titanium in the solution (alkalimetal/titanium) is in the range of 20/1 to 0.1/1.

If the alkali metal/titanium ratio is within the above range, a highquality polyester resin can be produced with high polymerizationactivity and improved solubility. If the amount used of the alkali metalcompound (b) is less than the above range, the effect to the activityand quality by containing the alkali metal compound (b) may not beobtained sufficiently. In addition, if the amount used of the alkalimetal compound (b) is more than the above range, to the contrary theactivity may decrease.

In the present invention, when the solid titanium-containing compound(a) is dissolved in ethylene glycol-containing solution (c) underpresence of the alkali metal compound (b), ethylene glycol-containingsolution (c) may include a solubilizing aid, if necessary. In addition,if the alkali metal compound (b) is not used when solidtitanium-containing compound (a) is dissolved in ethyleneglycol-containing solution (c), ethylene glycol-containing solution (c)may include a solubilizing aid and/or an acid component, if necessary.

The solubilizing aid includes glycerin, trimethylol propane, propyleneglycol, pentaerythritol, sorbitol and the like. Glycerin or trimethylolpropane is preferred.

The solubilizing aid is used in an amount of 1 to 50% by weight, andpreferably 1 to 25% by weight, relative to ethylene glycol-containingsolution (c).

The acid component includes organic sulfonic acid such as sulfuric acid,para-toluene sulfonic acid and the like; organic carboxylic acid such asoxalic acid, acetic acid, citric acid and the like. Sulfuric acid ororganic sulfonic acid is preferred.

The acid component is used in an amount of 0.1 to 20% by weight, andpreferably 0.1 to 10% by weight, relative to the ethyleneglycol-containing solution.

A titanium-containing solution which is a solution in which solidtitanium-containing compound (a) is dissolved in ethyleneglycol-containing solution (c), is prepared by a method as describedabove.

This titanium-containing solution is preferably transparent. HAZE valuemeasured by a hazemeter in the method as described below is 30% or less,preferably 20% or less, and more preferably 10% or less.

If HAZE value of the titanium-containing solution is within the aboverange, it is easy to add at the time of polymerization. If HAZE valueexceeds the above range, the cloudy components may be precipitated whilestanding in the long term.

The content of titanium derived from the solid titanium-containingcompound (a) in this titanium-containing solution is usually in therange of 500 to 100,000 ppm, preferably 3,000 to 100,000 ppm, and morepreferably 5,000 to 50,000 ppm.

In the present invention, the titanium content in thetitanium-containing solution can be measured, for example, by ICPanalysis.

If the content of titanium derived from the solid titanium-containingcompound (a) in this titanium-containing solution is within the aboverange, the amount of solvent which is added to the polymerizationreactor when catalyst is added to the polymerization reactor is not muchto affect polymerization, and further, dissolution of the solidtitanium-containing compound (a) into the reaction system is not hard.

Water content in the titanium-containing solution, is preferably in therange of 0.05 to 15.0% by weight, and more preferably 0.05 to 10% byweight. If the water content of titanium-containing solution is withinthe above range, preferably the solubility is good, and the storagestability is also good.

Method for Producing a Polyester Resin

In the method for producing a polyester resin of the present invention,aromatic dicarboxylic acid or an ester-forming derivative thereof andaliphatic diol or an ester-forming derivative thereof are subjected topolycondensation under presence of the above-described catalyst forpolyester production, to produce the polyester resin. Hereinafter, oneexample of the method will be explained.

(Raw Materials Used)

In the method for producing a polyester resin according to the presentinvention, aromatic dicarboxylic acid or an ester-forming derivativethereof and aliphatic diol or an ester-forming derivative thereof areused as raw materials.

The aromatic dicarboxylic acid which is used in the present inventionincludes aromatic dicarboxylic acid such as terephthalic acid, phthalicacid, isophthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethane dicarboxylic acid and the like.

The aliphatic diol includes aliphatic glycol such as ethylene glycol,trimethylene glycol, propylene glycol, tetramethylene glycol, neopentylglycol, hexamethylene glycol, dodecamethylene glycol and the like.

In the present invention, aliphatic dicarboxylic acid such as adipicacid, sebacic acid, azelainic acid, decane dicarboxylic acid and thelike, alicyclic dicarboxylic acid such as cyclohexane dicarboxylic acid,and the like can be further used as a raw material with the aromaticdicarboxylic acid. In addition, alicyclic glycol such as cyclohexanedimethanol and the like, aromatic diol such as bisphenol, hydroquinone,2,2-bis(4-β-hydroxyethoxyphenyl)propanes and the like can be furtherused as a raw material with the aliphatic diol.

Further, polyfunctional compound such as trimesinic acid, trimethylolethane, trimethylol propane, trimethylol methane, pentaerythritol andthe like can be used as a raw material in the present invention.

(Esterification Process)

First, aromatic dicarboxylic acid or an ester-forming derivative thereofand aliphatic diol or an ester-forming derivative thereof are subjectedto esterification to produce a polyester resin.

Specifically, a slurry including aromatic dicarboxylic acid or anester-forming derivative thereof and aliphatic diol or an ester-formingderivative thereof is prepared.

In such slurry, usually 1.005 to 1.4 mole, and preferably 1.01 to 1.3mole of aliphatic diol or an ester-forming derivative thereof iscontained, relative to 1 mole of aromatic dicarboxylic acid or anester-forming derivative thereof. This slurry is continuously providedto the esterification process.

Esterification is preferably carried out using a device in which atleast 2 reactive group for esterification are serially connected underthe condition of ethylene glycol reflux, with removing water produced bythe reaction to the outside of the distillation tower.

Esterification process is conducted usually in multiple steps. The firststep of the esterification is carried out under the condition that thereaction temperature is usually 240 to 270° C., and preferably 245 to265° C., and the pressure is 0.02 to 0.3 MPaG (0.2 to 3 kg/cm² G), andpreferably 0.05 to 0.2 MPaG (0.5 to 2 kg/cm² G). The last step of theesterification is carried out under the condition that the reactiontemperature is usually 250 to 280° C., and preferably 255 to 275° C. andthe pressure is 0 to 0.15 MPaG (0 to 1.5 kg/cm² G), and preferably 0 to0.13 MPaG (0 to 1.3 kg/cm² G).

If the esterification is conducted in two steps, the esterificationconditions of the first step and the second step are in theabove-described ranges, respectively. If the esterification is conductedin three or more steps, the esterification conditions in the second stepto the preceding step of the last step may be a condition between thereaction condition of the first step and the reaction condition of thelast step.

For example, if the esterification is conducted in 3 steps, the reactiontemperature of the second step of esterification is usually 245 to 275°C., and preferably 250 to 270° C., and the pressure is usually 0 to 0.2MPaG (0 to 2 kg/cm² G), and preferably 0.02 to 0.15 MPaG (0.2 to 1.5kg/cm² G).

The esterification rate in each step is not specially limited, but it ispreferred that the degree of increase of esterification rate in eachstep is distributed smoothly. For the esterification product of the laststep, usually 90% or more, and preferably 93% or more of esterificationrate is desired to be achieved.

By this esterification process, the esterification product (lowmolecular condensate) of aromatic dicarboxylic acid and aliphatic diolis obtained, and number-average molecular weight of this low molecularcondensate is approximately 500 to 5,000.

The low molecular condensate obtained by the above-describedesterification process is provided to the next polycondensation (liquidpolycondensation) process.

(Liquid Polycondensation Process)

In the liquid polycondensation process, the low molecular condensateobtained in the esterification process under presence of the catalystfor polyester production, is subjected to polycondensation by heating atthe temperature of the melting point of the polyester resin or higher(usually 250 to 280° C.) under reduced pressure. In thispolycondensation reaction, the reaction is preferably carried out withdistilling off the unreacted aliphatic diol out of the reaction system.

The polycondensation reaction may be conducted in one step or inmultiple steps. For example, when polycondensation reaction is carriedout in multiple steps, the first step of polycondensation reaction iscarried out under the condition that the reaction temperature is 250 to290° C., and preferably 260 to 280° C., and the pressure is 0.07 to0.003 MPaG (500 to 20 Torr), and preferably 0.03 to 0.004 MPaG (200 to30 Torr), and the last step of polycondensation reaction is carried outunder the condition that the reaction temperature is 265 to 300° C., andpreferably 270 to 295° C. and the pressure is 1 to 0.01 kPaG (10 to 0.1Torr), and preferably 0.7 to 0.07 kPaG (5 to 0.5 Torr).

If the polycondensation is conducted in three or more steps,polycondensation in the second step to the preceding step of the laststep may be conducted under the condition between the reaction conditionof the first step and the reaction condition of the last step. Forexample, if the polycondensation is conducted in 3 steps, the secondstep of polycondensation is conducted under the condition that thereaction temperature of is usually 260 to 295° C., and preferably 270 to285° C. and the pressure is 7 to 0.3 kPaG (50 to 2 Torr), and preferably5 to 0.7 kPaG (40 to 5 Torr).

In the polycondensation reaction, the solid titanium-containing compound(a) or the titanium-containing solution is desirably used in an amountof 0.001 to 0.2 mole %, and preferably 0.002 to 0.1 mole %, relative toaromatic dicarboxylic acid unit in the low molecular condensate in termsof converted metal atom.

If the compound (II) is further used in addition to the solidtitanium-containing compound (a) or the titanium-containing solution,the compound (II) is used in an amount of 0.001 to 0.5 mole %, andpreferably 0.002 to 0.3 mole %, relative to aromatic dicarboxylic acidunit in low molecular condensate in terms of converted metal atom.

In addition, if alkali metal compound (b) is further used in addition tothe solid titanium-containing compound (a) or the titanium-containingsolution, the alkali metal compound (b) is used in an amount of 0.001 to0.5 mole %, and preferably 0.002 to 0.3 mole %, relative to aromaticdicarboxylic acid unit in low molecular condensate in terms of convertedalkali metal atom.

A catalyst comprising at least one kind of solution selected from thesolid titanium-containing compound (a) or the titanium-containingsolution and, optionally the compound (II) and/or the alkali metalcompound (b) may be present in the polycondensation reaction. For this,the catalyst may be added in any processes of the process for preparinga slurry which is a raw material, the esterification process, the liquidpolycondensation process and the like. In addition, the catalyst may beadded at one time in whole amount or may be added multiple times individed amounts. In addition, if the compound (II) and/or the alkalimetal compound (b) is(are) combined, it(they) may be added in the sameprocess or in a separate process with the solid titanium-containingcompound (a) or the titanium-containing solution.

In addition, the polycondensation reaction is preferably carried outunder coexistence of a stabilizer.

The stabilizer specifically includes phosphorus compound such asphosphoric acid esters such as trimethyl phosphate, triethyl phosphate,tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate and thelike; phosphorous acid esters such as triphenyl phosphite, trisdodecylphosphite, trisnonylphenyl phosphate and the like; phosphoric acid esterand phosphoric acid such as methylacid phosphate, ethylacid phosphate,isopropylacid phosphate, butylacid phosphate, dibutyl phosphate,monobutyl phosphate, dioctyl phosphate and the like; polyphosphoricacid, and the like.

Such phosphorus compound may be added in an amount of 0.005 to 0.2 mole%, and preferably 0.01 to 0.1 mole %, relative to aromatic dicarboxylicacid in terms of converted phosphorus atom in the correspondingphosphorus compound.

The intrinsic viscosity [IV] of the polyester resin obtained in theliquid polycondensation process as described above is 0.40 to 1.0 dl/g,and preferably 0.50 to 0.90 dl/g. Further, intrinsic viscosity to beachieved in each step of the liquid polycondensation process except thelast step is not specially limited, but it is preferred that the degreeof increase of intrinsic viscosity in each step is distributed smoothly.

Further, in the present specification, intrinsic viscosity [IV] iscalculated by dissolving 1.2 g of the polyester resin in 15 cc ofo-chlorophenol under heating, and then cooling the solution andmeasuring the solution viscosity at 25  C.

The polyester resin obtained in the polycondensation process is usuallymolded to particulates (chip shape) by melt extrusion molding.

(Solid Polycondensation Process)

The polyester resin obtained in the liquid polycondensation process canbe further subjected to solid polycondensation, if desired.

The particulate polyester resin to be provided to the solidpolycondensation process may be preliminarily subject toprecrystallization by heating at a temperature lower than thetemperature of the solid polycondensation, before provided to the solidpolycondensation process.

Such precrystallization process can be carried out by heating theparticulate polyester resin in dried state at a temperature of usually120 to 200° C. and preferably 130 to 180° C. for 1 minute to 4 hours. Inaddition, such precrystallization can be also carried out by heating theparticulate polyester resin at a temperature of 120 to 200° C. for atleast 1 minute under water vapor atmosphere, under watervapor-containing inert gas atmosphere, or under water vapor-containingair atmosphere.

The degree of crystallization of the precrystallized polyester resin ispreferably 20 to 50%.

Further, so-called solid polycondensation reaction of the polyesterresin does not proceed by this precrystallization treatment, and theintrinsic viscosity of the precrystallized polyester resin is almost thesame as the intrinsic viscosity of the polyester resin after the liquidpolycondensation. Difference between the intrinsic viscosity of theprecrystallized polyester resin and the intrinsic viscosity of thepolyester resin before the precrystallization is usually 0.06 dl/g orless.

The solid polycondensation process comprises at least 1 step, and isconducted under inert gas atmosphere of nitrogen, argon, carbon dioxideand the like, under the condition that the temperature is 190 to 230°C., and preferably 195 to 225° C., and the pressure is 98 to 0.001 MPaG(1 kg/cm² G to 10 Torr), and preferably atmospheric pressure to 0.01MPaG (100 Torr). The inert gas to be used is desirably nitrogen gas.

The particulate polyester resin obtained by such solid polycondensationprocess may be treated with water, for example, by the method asdescribed in Japanese Examined Patent Application Publication No.7-64920. This water treatment is conducted by contacting the particulatepolyester resin with water, water vapor, water vapor-containing inertgas, water vapor-containing air and the like.

It is desired that the intrinsic viscosity of thus obtained particulatepolyester resin is usually 0.60 dl/g or more, preferably 0.60 to 1.00dl/g, and more preferably 0.75 to 0.95 dl/g.

The process for producing the polyester resin comprising theabove-described esterification process and the polycondensation processcan be carried out by any one of batch type, semi-continuation type orcontinuation type.

The catalyst for polyester production according to the presentinvention, in particular, the catalyst comprising the solidtitanium-containing compound (a) or the titanium-containing solution andthe compound (II) wherein the compound (II) is a magnesium compound, issuitable as a catalyst for producing polyethylene terephthalate. Inproducing polyethylene terephthalate with the catalyst comprising thesolid titanium-containing compound (a) or the titanium-containingsolution and the magnesium compound, esterification, liquidpolycondensation and, if desired, solid polycondensation are conductedas described above using, for example, terephthalic acid or anester-forming derivative thereof, ethylene glycol or an ester-formingderivative thereof, and if necessary, aromatic dicarboxylic acid otherthan terephthalic acid and/or aliphatic diol other than ethylene glycolas raw materials.

In this regard, terephthalic acid or an ester-forming derivative thereofis used in an amount of at least 80 mole %, and preferably at least 90mole %, relative to 100 mole % of aromatic dicarboxylic acid, ethyleneglycol or an ester-forming derivative thereof is used in an amount of atleast 80 mole %, and preferably at least 90 mole %, relative to 100 mole% of aliphatic diol.

The titanium content of thus obtained polyethylene terephthalate ispreferably in the range of 1 to 200 ppm, and particularly 1 to 50 ppm,and magnesium content is preferably in the range of 1 to 200 ppm, andparticularly 1 to 100 ppm. In addition, it is desired that the weightratio of titanium and magnesium contained in the polyethyleneterephthalate (Mg/Ti) is in the range of 0.01 or more, preferably 0.06to 10, and particularly preferably 0.06 to 5. Further, the chlorinecontent of the polyethylene terephthalate is in the range of 0 to 1,000ppm, and preferably 0 to 100 ppm.

Such polyethylene terephthalate has excellent hue and in particularexcellent transparency, and has low acetaldehyde content, so it isparticularly preferably used as a hollow molded container.

By using the catalyst for polyester production according to the presentinvention, a polyester resin can be produced at comparable or moreproduction rate as compared with the polyester resin produced by usingthe antimony compound or germanium compound that is currently used inthe industry as shown in Formula (A-1) as above.

The polyester resin produced by using the catalyst for polyesterproduction according to the present invention has comparable or lessamount of increase in the acetaldehyde at the time of molding ascompared with that of the polyester resin produced by using the antimonycompound or germanium compound that is currently used in the industry asshown in Formula (B-1). In other words, by using the polyester resinaccording to the present invention, a beverage packaging container canbe produced in comparable or better quality as compared with thatobtained by using the antimony compound or germanium compound.

By using the catalyst for polyester production according to the presentinvention, the metal content in the polyester resin can decrease to 50ppm or less as shown in Formula (C-1), and therefore a polyester resinwhich has comparable or better environment safety as compared with thepolyester resin produced by using the existing antimony compound orgermanium compound, is produced. It is preferred that the catalyst forpolyester production according to the present invention substantiallycomprises no antimony compound and germanium compound as apolycondensation catalyst.

Thus produced polyester resin may contain conventionally well-knownadditives, for example, a stabilizer, a mold release agent, anantistatic agent, a dispersing agent, a coloring agent such as a pigmentand a dye, and the like. These additives may be added in any steps inthe polyester production, or may be added by master-batch before moldingprocess.

The polyester resin obtained by the present invention can be used as amaterial for various molded bodies, for example, hollow molded bodiessuch as a hollow molded container by melt-molding, sheets, films, fibersand the like, and preferably for a hollow molded container.

For a method for molding a hollow molded container, sheets, films,fibers and the like from the polyester resin, and particularly thepolyethylene terephthalate obtained by the present invention, anyconventionally well-known methods can be employed.

For example, a hollow molded container may be produced by a method forproducing a hollow molded article in which the polyester resin isextruded in the melt state by a die to form a parison in tube form, thenthe parison is maintained in a mold of desired shape, air is blown, andit is introduced to a mold; a method for producing a hollow moldedarticle in which the polyester resin is injection-molded to produce apreform, the preform is heated to suitable extension temperature, thenthe preform is maintained in a mold of desired shape, air is blown, andit is introduced to a mold; and the like.

EXAMPLES

Hereinafter, the present invention will be explained by the followingExamples, which are not intended to limit the present invention.

Reference Example 1

Into a 1,000-ml glass beaker was put 500 ml of deionized water, thebeaker was cooled in an ice bath, and 5 g of titanium tetrachloride wasadded dropwise with stirring. When hydrochloride stopped to occur, thesolution was taken out of the ice bath, 25% ammonia water was addeddropwise at room temperature with stirring, and the pH of the solutionwas adjusted to 9. To this solution was added dropwise 15% aqueousacetate solution at room temperature with stirring, and the pH of thesolution was adjusted to 5. The produced precipitate was isolated byfiltration. The precipitate was washed five times with deionized water.The precipitate after washing was soaked in water containing 20% byweight of ethylene glycol for 30 minutes, and solid-liquid separationwas conducted by filtration in the same manner as at the time ofwashing. Titanium compound after washing was dried under reducedpressure (40° C., 1.3 kPa (10 Torr), 20 hours) to remove moisture, togive a solid hydrolysate (a solid titanium-containing compound). Theobtained solid titanium-containing compound was milled into particles ofapproximately 10 to 20 μm before dissolving in ethylene glycol.

The metal titanium content in the solid titanium-containing compound asmeasured by ICP analysis was 35.4% by weight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid titanium-containing compound in ethyleneglycol was 3,000 ppm, the carbon content was 11.8% by weight, and theweight ratio of titanium and carbon (Ti/C) was 3.

Then, into a 200-ml glass flask was put 100 g of ethylene glycol, and tothe flask was added 0.34 g of the solid titanium-containing compound.The mixture was dissolved by heating at 150° C. for 1 hour, to give atitanium-containing solution. The titanium content in thetitanium-containing solution as measured by ICP analysis was 0.12% byweight. In addition, HAZE value of this solution as measured byhazemeter (Nippondenshoku Co., Ltd., ND-10001DP) was 1.5%.

Reference Example 2

Into a 1,000-ml glass beaker was put 500 ml of deionized water, thebeaker was cooled in an ice bath, and 5 g of titanium tetrachloride wasadded dropwise with stirring. When hydrochloride stopped to occur, thesolution was taken out of the ice bath, 25% ammonia water was addeddropwise at room temperature with stirring, and the pH of the solutionwas adjusted to 9. To this solution was added dropwise 15% aqueousacetate solution at room temperature with stirring, and the pH of thesolution was adjusted to 5. The produced precipitate was isolated byfiltration. The precipitate after washing was maintained as a slurry of2.0% by weight slurry concentration, in water containing 30% by weightethylene glycol for 30 minutes. Granulating and drying were carried outusing a spray drier of dual fluid nozzle type at a temperature of 90°C., to give a solid hydrolysate (a solid titanium-containing compound).

Particle size distribution of the obtained solid titanium-containingcompound was 0.5 to 20 μm, and the mean particle diameter was 1.8 μm.

The metal titanium content in the solid titanium-containing compound asmeasured in the same manner as in Reference Example 1 was 34.8 was % byweight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid hydrolysate in ethylene glycol was 3,000ppm, the carbon content was 11.6% by weight, and the weight ratio oftitanium and carbon (Ti/C) was 3.

Then, into a 300-ml glass flask were put 170 g of ethylene glycol and 30g of glycerin, and to the flask was added 5.75 g of the solidtitanium-containing compound. The mixture was dissolved by heating at170° C. for 2 hours, to give a titanium-containing solution. Thetitanium content in the titanium-containing solution as measured by ICPanalysis was 1.0% by weight, and HAZE value as measured in the samemanner as in Reference Example 1 was 1.3%.

Reference Example 3

Into a 2,000-ml glass flask was put 1000 ml of deionized water, and 8.7g of zinc acetate dihydrate was dissolved in the water. Subsequently, 66g of 5% aqueous solution of sodium hydroxide was added, and the pH wasadjusted to 11. Thus produced precipitate was isolated by filtration,and washed five times with deionized water. 9 g of thus obtainedprecipitate and, 78 g of the precipitate of the titanium compound afterwashing, prepared by the same formulation as in Example 1 (titaniumcontent: 5.4% by weight), were mixed. The mixture was soaked in watercontaining 20% by weight of ethylene glycol for 30 minutes, andsolid-liquid separation was conducted by filtration in the same manneras at the time of washing. The precipitate after washing was dried underreduced pressure (40° C., 1.3 kPa (10 Torr), 20 hours) to removemoisture, to give a solid hydrolysate (a solid titanium-containingcompound). The obtained solid titanium-containing compound was milledinto particles of approximately 10 to 20 μm before dissolving inethylene glycol.

The titanium content in the solid titanium-containing compound asmeasured by ICP analysis was 30.2% by weight, and the zinc content was16.8% by weight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—C—C bond, was confirmed byelement analysis, EXAFS analysis and 13C-NMR analysis. In addition, themaximum solubility of the solid hydrolysate in ethylene glycol was 3,000ppm, the carbon content was 10.1% by weight, and the weight ratio oftitanium and carbon (Ti/C) was 3.

Then, into a 200-ml glass flask was put 100 g of ethylene glycol, and tothe flask was added 0.5 g of p-toluene sulfonic acid, and then was added0.38 g of the solid titanium-containing compound. The mixture wasdissolved by heating at 150° C. for 1 hour, to give atitanium-containing solution. The titanium content in the obtainedtitanium-containing solution as measured by ICP analysis was 0.12% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 5.2%.

Reference Example 4

Into a 1,000-ml glass beaker was put 500 ml of deionized water, and 0.15g of magnesium hydroxide anhydride was added and dispersed. The beakerwas cooled in an ice bath, and 5 g of titanium tetrachloride was addeddropwise with stirring. The solution was acidified during the dropping,and the dispersed magnesium hydroxide was dissolved. When hydrochloridestopped to occur, the solution was taken out of the ice bath, 25%ammonia water was added dropwise at room temperature with stirring, andthe pH of the solution was adjusted to 9. To this solution was addeddropwise 15% aqueous acetate solution at room temperature with stirring,and the pH of the solution was adjusted to 5. The produced precipitateof hydrolysate was isolated by filtration. This precipitate was washedfive times with deionized water. The precipitate after washing wassoaked in water containing 10% by weight of ethylene glycol for 30minutes, and solid-liquid separation was conducted by filtration in thesame manner as at the time of washing. The hydrolysate after washing wasdried under reduced pressure (40° C., 1.3 kPa (10 Torr), 20 hours) toremove moisture, to give a solid hydrolysate (a solidtitanium-containing compound). The obtained solid titanium-containingcompound was milled into particles of approximately 10 to 20 μm beforebeing used as a polycondensation catalyst.

The metal titanium content in the solid titanium-containing compound asmeasured by ICP analysis was 33.4% by weight, and metal magnesiumcontent was 3.2% by weight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid hydrolysate in ethylene glycol was 3,000ppm, the carbon content was 11.1% by weight, and the weight ratio oftitanium and carbon (Ti/C) was 3.

Then, into a 200-ml glass flask was put 100 g of ethylene glycol, and tothe flask was add 0.5 g of p-toluene sulfonic acid, and then 0.36 g ofthe solid titanium-containing compound. The mixture was dissolved byheating at 150° C. for 1 hour, to give a titanium-containing solution.The titanium content in the titanium-containing solution as measured byICP analysis was 0.12% by weight, and HAZE value as measured in the samemanner as in Reference Example 1 was 5.4%.

Preparative Example 1

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 1.74 g of sodium hydroxide, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 2

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 1.43 g of potassium hydroxide, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 3

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 2.35 g of sodium methoxide, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 4

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 3.56 g of sodium acetate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 5

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 9.65 g of sodium laurate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 6

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 12.1 g of sodium palmitate, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 7

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 13.3 g of sodium stearate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 8

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 4.87 g of sodium lactate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 9

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 3.74 g of trisodium citrate, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 10

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 7.35 g of sodium glutamate, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Example 1

Production of Polyester

Into a reactor having previously 33,500 parts by weight of reactionsolution (in normal operation) was continuously fed a slurry which wasprepared by mixing 6,458 parts by weight/hour of high purityterephthalic acid and 2,615 parts by weight/hour of ethylene glycolwhile maintaining the condition of nitrogen atmosphere, 260° C. and 0.9kg/cm² G (0.09 MPaG) with stirring to conduct esterification. In thisesterification, the mixed solution of water and ethylene glycol wasdistilled off.

The esterification product (low molecular condensate) was controlled tohave 3.5 hours of mean retention hour, and continuously extracted out ofthe system.

Number-average molecular weight of the obtained low molecular condensateof ethylene glycol and terephthalic acid was 600 to 1,300 (trimer topentamer).

Ethylene glycol solution of the titanium catalyst prepared in ReferenceExamples 1 to 4, and ethylene glycol solution of the alkali metalcompound, or the alkali metal compound in the undissolved solid stateprepared in Preparative Examples 1 to 10, were combined and used asshown in Table 1, to produce a polycondensation catalyst, andpolycondensation reaction for the obtained low molecular condensate wasconducted with the polycondensation catalyst.

Regarding the amount of each catalyst, the solution of ReferenceExamples 1 to 4 was added in an amount of 18 ppm in terms of convertedtitanium atom, relative to the produced polyethylene terephthalate. Thesolution of Preparative Examples 1 to 10 or solid alkali metal compoundas alkali metal compound was added in an amount of 18 ppm of sodium and30 ppm of potassium in terms of converted alkali metal, relative to theproduced polyethylene terephthalate. Further, phosphoric acid was addedin an amount of 6 ppm in terms of converted phosphorus atom, relative tothe produced polyethylene terephthalate. The polycondensation wascarried out under condition of 285° C. and 0.1 kPa (1 Torr). The timerequired for obtaining a liquid polymer product, polyethyleneterephthalate which is a liquid polycondensation product, having anintrinsic viscosity of 0.64 dl/g was measured.

Then, the obtained polyethylene terephthalate which is a liquid polymerproduct, was subjected to precrystallization at 170° C. for 2 hours, andheated at 220° C. under nitrogen gas atmosphere so that intrinsicviscosity was elevated from 0.64 dl/g to 0.84 dl/g by elevating themolecular weight with the solid phase polymerization. The solidpolycondensation time (h) required for the solid polycondensation wasmeasured. The results are as shown in Table 1.

Molding of a Preform

Polyethylene terephthalate obtained by the solid phase polymerizationwas dried at 170° C. for 4 hours with a dehumidifying air dryer. Watercontent in the resin after drying was 40 ppm or less. The driedpolyethylene terephthalate was molded with ASB-50 (manufactured byNISSEI ASB MACHINE CO., LTD.) at a cylinder temperature of 265 to 275°C. and 26±1 seconds of a molding cycle, to obtain a preform.

Measurement of Acetaldehyde Content

For the obtained polyethylene terephthalate which is a solid polymerproduct, and preform, the acetaldehyde content was measured by thefollowing method, and the stability parameter of the polyester resin(ΔAA) was calculated. The results are shown in Table 1.

The acetaldehyde content was measured with a gas chromatography (GC-6A,manufactured by SHIMADZU Corporation) for a supernatant which isobtained by freeze-milling 2.0 g of the sample with a freezer mill,putting the milled sample in to a nitrogen-flushed vial, further puttinginternal standard substance (acetone) and water, sealing the vial, andheating the vial at 120±2° C. for 1 hour with a dryer.

Comparative Example 1

Into a 1,000-ml glass beaker was put 500 ml of deionized water, thebeaker was cooled in an ice bath, and 5 g of titanium tetrachloride wasadded dropwise with stirring. When hydrochloride stopped to occur, thesolution was taken out of the ice bath, 25% ammonia water was addeddropwise at room temperature with stirring, and the pH of the solutionwas adjusted to 9. To this solution was added dropwise 15% aqueousacetate solution at room temperature with stirring, and the pH of thesolution was adjusted to 5. The produced precipitate was isolated byfiltration. This precipitate was washed five times with deionized water.Solid-liquid separation after washing was conducted by filtration in thesame manner. Titanium compound after washing was dried under reducedpressure (40° C., 10 Torr and 20 hours) to remove moisture, to give ahydrolysate.

The obtained solid hydrolysate was milled into particles ofapproximately 10 to 20 micron before dissolving in ethylene glycol.

The metal titanium content in the solid hydrolysate as measured in thesame manner as in Reference Example 1 was 50.7% by weight.

The fact that the solid hydrolysate contains titanium, oxygen, carbonand hydrogen and has Ti—O—C bond, was confirmed by element analysis andEXAFS analysis. Further, the carbon content was 0.5% by weight. Inaddition, the maximum solubility of the solid titanium-containingcompound in ethylene glycol was 500 ppm.

Into a 200-ml glass flask was put 120 g of ethylene glycol, and to theflask was added 2.36 g of the solid titanium-containing compound. Themixture was heated at 170° C. for 2 hours, but the solidtitanium-containing compound did not dissolve.

Comparative Example 2

Polycondensation reaction was conducted in the same manner as in Example1 except antimony acetate which is industrially used currently, was usedas a catalyst. Antimony acetate was added in an amount of 160 ppm interms of converted antimony atom, relative to the produced polyethyleneterephthalate, and further phosphoric acid was added in an amount of 15ppm in terms of converted phosphorus atom, relative to the producedpolyethylene terephthalate.

Comparative Example 3

Polycondensation reaction was conducted in the same manner as inComparative Example 2 except antimony acetate was added in an amount of225 ppm in terms of converted antimony atom, relative to the producedpolyethylene terephthalate.

Table 1 indicates the liquid polycondensation time, the solidpolycondensation time, the total amount of the metal atoms contained inthe polyester resin (M), the total amount of the heavy metal atomscontained in the polyester resin (HM), the value of polymerizabilityparameter (V_(ssp)), the intrinsic viscosity before solidpolycondensation ([AA]₀), the intrinsic viscosity after solidpolycondensation ([AA]₁) and difference between the acetaldehydecontents before and after molding (ΔAA) in Example 1 and ComparativeExamples 2 and 3.

TABLE 1 Liquid Solid Catalyst Used Polycondensation Polycondensation MHM V_(ssp) [AA]₀ [AA]₁ ΔAA Ti Alkali Metal Time (h) Time (h) (ppm) (ppm)(dl/g · h) (ppm) (ppm) (ppm) Example 1 Reference Preparative Example 11.6 7.3 36 0 0.0274 1.0 6.3 5.3 Example 1 Preparative Example 2 1.8 7.948 0 0.0253 1.0 6.0 5.0 Preparative Example 3 1.7 7.4 36 0 0.0270 1.06.2 5.2 Preparative Example 4 1.4 7.5 36 0 0.0267 1.1 6.4 5.3Preparative Example 5 1.4 7.5 36 0 0.0267 1.1 6.3 5.2 PreparativeExample 6 1.4 7.3 36 0 0.0274 1.2 6.4 5.2 Preparative Example 7 1.5 7.436 0 0.0270 1.1 6.3 5.2 Preparative Example 8 1.5 7.2 36 0 0.0278 1.16.4 5.3 Preparative Example 9 1.4 7.4 36 0 0.0270 1.2 6.4 5.2Preparative Example 10 1.5 7.5 36 0 0.0267 1.1 6.5 5.4 ReferencePreparative Example 1 1.7 7.4 36 0 0.0270 1.2 6.2 5.0 Example 2Preparative Example 2 1.8 7.9 48 0 0.0253 1.0 6.0 5.0 PreparativeExample 3 1.6 7.5 36 0 0.0267 1.1 6.3 5.2 Preparative Example 4 1.5 7.636 0 0.0263 1.2 6.5 5.3 Preparative Example 5 1.4 7.4 36 0 0.0270 1.16.4 5.3 Preparative Example 6 1.5 7.3 36 0 0.0274 1.2 6.3 5.1Preparative Example 7 1.5 7.4 36 0 0.0270 1.1 6.3 5.2 PreparativeExample 8 1.4 7.3 36 0 0.0274 1.1 6.4 5.3 Preparative Example 9 1.5 7.536 0 0.0267 1.1 6.4 5.3 Preparative Example 10 1.5 7.6 36 0 0.0263 1.16.5 5.4 Na Acetate 1.6 7.6 36 0 0.0263 1.2 6.5 5.3 Na Stearate 1.5 7.436 0 0.0270 1.2 6.3 5.1 Tri-Na Citrate 1.5 7.5 36 0 0.0267 1.1 6.4 5.3Na Glutamate 1.5 7.6 36 0 0.0263 1.1 6.5 5.4 Reference PreparativeExample 1 1.5 7.0 46 10 0.0286 1.1 6.6 5.5 Example 3 ReferencePreparative Example 1 1.6 7.2 38 0 0.0278 1.1 6.5 5.4 Example 4Comparative Sb Acetate 2.4 9.0 160 160 0.0222  1.1. 7.0 5.9 Example 2Comparative Sb Acetate 1.4 7.0 225 225 0.0286 1.2 8.0 6.8 Example 3

Reference Example 5

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added and dissolved 1.74 g of sodium hydroxide. Afterdissolution, 2.83 g of the solid titanium-containing compound preparedin Reference Example 1 was added, and the he mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. Titanium contentin the titanium-containing solution as measured by ICP analysis was0.98% by weight, and HAZE value as measured in the same manner as inReference Example 1 was 1.3%.

Reference Example 6

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 5.80 g of 30% by weight aqueous solution of sodiumhydroxide, and the contents were mixed. This mixture was heated at 120°C. to distill off 3.0 g of water. Then, 2.83 g of the solidtitanium-containing compound prepared in Reference Example 1 was added,and the mixture was dissolved by heating at 125° C. for 30 minutes, togive a titanium-containing solution which is a catalyst for polyesterproduction. The titanium content in the titanium-containing solution asmeasured by ICP analysis was 0.96% by weight, and HAZE value as measuredin the same manner as in Reference Example 1 was 1.2%.

Reference Example 7

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 5.80 g of 30% by weight aqueous solution of sodiumhydroxide and the contents were mixed. 2.83g of the solidtitanium-containing compound prepared in Reference Example 1 was addedto this solution, and the mixture was dissolved by heating at 120° C.for 30 minutes, to give a titanium-containing solution which is acatalyst for polyester production. The titanium content in thetitanium-containing solution as measured by ICP analysis was 0.93% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.1%.

Reference Example 8

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added and dissolved 2.35 g of sodium methoxide. Afterdissolution, 2.83 g of the solid titanium-containing compound preparedin Reference Example 1 was added, and the mixture was dissolved byheating at 125° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.97% by weight, and HAZE value as measured in the same manner as inReference Example 1 was 1.2%.

Reference Example 9

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added and dissolved 0.87 g of sodium hydroxide. Afterdissolution, 2.83 g of the solid titanium-containing compound preparedin Reference Example 1 was added, and the mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.99% by weight, and HAZE value as measured in the same manner as inReference Example 1 was 1.4%.

Reference Example 10

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added and dissolved 3.09 g of sodium hydroxide. Afterdissolution, 2.83 g of the solid titanium-containing compound preparedin Reference Example 1 was added, and the mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.98% by weight, and HAZE value as measured in the same manner as inReference Example 1 was 1.2%.

Reference Example 11

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added and dissolved 2.49 g of potassium hydroxide. Afterdissolution, 2.83 g of the solid titanium-containing compound preparedin Reference Example 1 was added, and the mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.98% by weight, and HAZE value as measured in the same manner as inReference Example 1 was 1.2%.

Reference Example 12

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 1.74 g of sodiumhydroxide. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution which is a catalyst for polyesterproduction. The titanium content in the titanium-containing solution asmeasured by ICP analysis was 1.0% by weight, and HAZE value as measuredin the same manner as in Reference Example 1 was 1.0%.

Reference Example 13

Into a 1,000-ml glass beaker was put 500 ml of deionized water, thebeaker was cooled in an ice bath, and 5 g of titanium tetrachloride wasadded dropwise with stirring. When hydrochloride stopped to occur, thesolution was taken out of the ice bath, 25% ammonia water was addeddropwise at room temperature with stirring, and the pH of the solutionwas adjusted to 5. The produced precipitate was isolated by filtration.This precipitate was washed five times with deionized water. Theprecipitate after washing was soaked in water containing 20% by weightof ethylene glycol for 30 minutes, and solid-liquid separation wasconducted by filtration in the same manner as at the time of washing.Titanium compound after washing was dried under reduced pressure (40°C., 1.3 kPa (10 Torr), 20 hours) to remove moisture, to give a solidhydrolysate (a solid titanium-containing compound).

Thus obtained solid titanium-containing compound was milled intoparticles of approximately 10 to 20 μm before dissolving in ethyleneglycol.

The metal titanium content in the solid titanium-containing compound asmeasured in the same manner as in Reference Example 1 was 34.6% byweight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid titanium-containing compound in ethyleneglycol was 3,000 ppm, the carbon content was 11.5% by weight, and theweight ratio of titanium and carbon (Ti/C) was 3.

Then, into a 300-ml glass flask was put 200 g of ethylene glycol, and tothe flask was added and dissolved 3.48 g of sodium hydroxide. Afterdissolution, 5.78 g of the solid titanium-containing compound was added,and the mixture was dissolved by heating at 120° C. for 30 minutes, togive a titanium-containing solution which is a catalyst for polyesterproduction. The titanium content in the titanium-containing solution asmeasured by ICP analysis was 0.98% by weight. In addition, and HAZEvalue as measured in the same manner as in Reference Example 1 was 1.3%.

Reference Example 14

Into a 1,000-ml glass beaker was put 500 ml of deionized water, thebeaker was cooled in an ice bath, 7.5 g of titanium tetraisopropoxidewas added dropwise with stirring. After finishing the dropping, themixture was stirred at room temperature for 30 minutes. After finishingthe stirring, the produced precipitate was isolated by filtration. Theprecipitate was soaked in water containing 20% by weight of ethyleneglycol for 30 minutes, and solid-liquid separation was conducted byfiltration in the same manner as at the time of washing. Titaniumcompound after washing was dried under reduced pressure (40° C., 1.3 kPa(10 Torr), 20 hours) to remove moisture, to give a solid hydrolysate (asolid titanium-containing compound).

Thus obtained solid titanium-containing compound was milled intoparticles of approximately 10 to 20 μm before dissolving in ethyleneglycol.

The metal titanium content in the solid titanium-containing compound asmeasured in the same manner as in Reference Example 1 was 36.3% byweight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid titanium-containing compound in ethyleneglycol was 3,000 ppm, the carbon content was 11.4% by weight, and theweight ratio of titanium and carbon (Ti/C) was 3.

Then, into a 300-ml glass flask was put 200 g of ethylene glycol, and tothe flask was added and dissolved 3.48 g of sodium hydroxide. Afterdissolution, 5.51 g of the solid titanium-containing compound was added,and the mixture was dissolved by heating at 120° C. for 30 minutes, togive a titanium-containing solution which is a catalyst for polyesterproduction. The titanium content in the titanium-containing solution asmeasured by ICP analysis was 0.98% by weight. In addition, HAZE value asmeasured in the same manner as in Example 1 was 1.2%.

Reference Example 15

Into a 300-ml glass flask was put 200 g of ethylene glycol, and to theflask was added and dissolved 3.48 g of sodium hydroxide. Afterdissolution, 5.75 g of the solid titanium-containing compound preparedin Reference Example 2 was added, and the mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.98% by weight. In addition, and HAZE value as measured in the samemanner as in Reference Example 1 was 1.3%.

Reference Example 16

Into a 300-ml glass flask was put 200 g of ethylene glycol, and to theflask was added and dissolved 3.48 g of sodium hydroxide. Afterdissolution, 6.62 g of the solid titanium-containing compound preparedin Reference Example 3 was added, and the mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.98% by weight, and metal zinc content was 0.54% by weight. HAZEvalue as measured in the same manner as in Reference Example 1 was 2.0%.

Reference Example 17

Then, into a 300-ml glass flask was put 200 g of ethylene glycol, and tothe flask was added and dissolved 3.48 g of sodium hydroxide. Afterdissolution, 5.99 g of the solid titanium-containing compound preparedin Reference Example 4 was added, and the mixture was dissolved byheating at 120° C. for 30 minutes, to give a titanium-containingsolution which is a catalyst for polyester production. The titaniumcontent in the titanium-containing solution as measured by ICP analysiswas 0.98% by weight, and metal magnesium content was 0.09% by weight.HAZE value as measured in the same manner as in Reference Example 1 was2.2%.

Reference Example 18

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 4.28 g of sodiumacetate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added to the flask, and themixture was dissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 1.0% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.1%.

Reference Example 19

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 11.6 g of sodiumlaurate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 0.99% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.2%.

Reference Example 20

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 14.5 g of sodiumpalmitate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 1.01% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.2%.

Reference Example 21

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 16.0 g of sodiumstearate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 0.98% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.2%.

Reference Example 22

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 5.79 g of sodiumlactate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 1.0% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.3%.

Reference Example 23

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 4.48 g of trisodiumcitrate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 1.01% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.2%.

Reference Example 24

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, and to the flask was added and dissolved 9.80 g of sodiumglutamate. After dissolution, 3.38 g of the solid titanium-containingcompound prepared in Reference Example 1 was added, and the mixture wasdissolved by heating at 120° C. for 30 minutes, to give atitanium-containing solution. The metal titanium content in thetitanium-containing solution as measured by ICP analysis was 1.0% byweight, and HAZE value as measured in the same manner as in ReferenceExample 1 was 1.1%.

Comparative Example 4

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added and dissolved 1.74 g of sodium hydroxide. Afterdissolution, 1.97 g of solid hydrolysate prepared in Comparative Example1 was added. The mixture was heated at 140° C. for 3 hours, but thesolid hydrolysate did not dissolve with no change in a cloudy state.

The metal titanium content in the slurry as measured by ICP analysis inthe same manner was 1.01% by weight.

Comparative Example 5

Into a 200-ml glass flask were put 102 g of ethylene glycol and 18 g ofglycerin, 3.38 g of solid hydrolysate prepared in Reference Example 1was added, and the mixture was dissolved by heating at 170° C. for 2hours, to give a solution which is a catalyst for polyester production.The metal titanium content in the solution as measured by ICP analysiswas 1.0% by weight, and HAZE value as measured in the same manner as inReference Example 1 was 2.0%.

Example 2

Production of Polyester

Polycondensation reaction for the low molecular condensate obtained inExample 1 was conducted with the titanium-containing solution or theethylene glycol solution of titanium catalyst prepared in ReferenceExamples 5 to 24 and Comparative Examples 4 and 5 as a polycondensationcatalyst.

Regarding the amount of each catalyst, the solution of ReferenceExamples 5 to 24 was added in an amount of 18 ppm in terms of convertedtitanium atom, relative to the produced polyethylene terephthalate, andfurther phosphoric acid was added in an amount of 6 ppm in terms ofconverted phosphorus atom, relative to the produced polyethyleneterephthalate. The time required for obtaining polyethyleneterephthalate which is a liquid polymer product, the solidpolycondensation time (T), the acetaldehyde content in the solid phasepolymerization product and the preform, and the stability parameter(ΔAA) were measured in the same manner as in Example 1.

Table 2 indicates the liquid polycondensation time, the solidpolycondensation time, and the values of M, HM, V_(ssp) [AA]₀, [AA]₁ andΔAA in Example 2 and Comparative Examples 4 and 5.

TABLE 2 Liquid Solid Polycondensation Polycondensation M V_(ssp) [AA]₀[AA]₁ ΔAA Catalyst Used Time (h) Time (h) (ppm) HM (ppm) (dl/g · h)(ppm) (ppm) (ppm) Example 2 Reference Example 5 1.5 7.4 36 0 0.0270 1.06.2 5.2 Reference Example 6 1.4 7.5 36 0 0.0267 1.2 6.3 5.1 ReferenceExample 7 1.5 7.7 36 0 0.0260 1.0 6.2 5.2 Reference Example 8 1.4 7.3 360 0.0274 1.2 6.4 5.2 Reference Example 9 1.3 7.2 27 0 0.0278 1.2 6.5 5.3Reference Example 10 1.6 7.8 50 0 0.0256 1.0 5.8 4.8 Reference Example11 1.5 7.7 48 0 0.0260 1.2 6.3 5.1 Reference Example 12 1.3 7.2 36 00.0278 1.1 6.3 5.2 Reference Example 13 1.5 7.5 36 0 0.0267 1.0 6.2 5.2Reference Example 14 1.5 7.6 36 0 0.0263 1.2 6.4 5.2 Reference Example15 1.4 7.4 36 0 0.0270 1.1 6.2 5.1 Reference Example 16 1.2 7.0 46 100.0286 1.2 6.7 5.5 Reference Example 17 1.3 7.3 38 0 0.0274 1.1 6.5 5.4Reference Example 18 1.5 7.6 36 0 0.0263 1.3 6.7 5.4 Reference Example19 1.4 7.3 36 0 0.0274 1.1 6.5 5.4 Reference Example 20 1.4 7.4 36 00.0270 1.2 6.3 5.1 Reference Example 21 1.4 7.3 36 0 0.0274 1.2 6.4 5.2Reference Example 22 1.4 7.4 36 0 0.0270 1.1 6.6 5.5 Reference Example23 1.4 7.5 36 0 0.0267 1.3 6.7 5.4 Reference Example 24 1.4 7.3 36 00.0274 1.1 6.5 5.1 Comparative Comparative 2.0 10.5 36 0 0.0190 1.1 6.04.9 Example 4 Example 4 Comparative Comparative 1.3 8.2 18 0 0.0244 1.210.0 8.8 Example 5 Example 5

Reference Example 25

The same procedures were conducted as in Reference Example 5 except thatthe amount of sodium hydroxide used was 0.87 g, to give atitanium-containing solution which is a catalyst for polyesterproduction. The titanium content in the titanium-containing solution asmeasured by ICP analysis was 0.98% by weight, and HAZE value as measuredin the same manner as in Reference Example 1 was 1.5%.

Reference Example 26

The same procedures were conducted as in Reference Example 21 exceptthat the amount of sodium stearate used was 8.0 g, to give atitanium-containing solution which is a catalyst for polyesterproduction. The metal titanium content in the titanium-containingsolution as measured by ICP analysis was 0.98% by weight, and HAZE valueas measured in the same manner as in Reference Example 1 was 1.3%.

Preparative Example 11

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 0.87 g of sodium hydroxide, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 12

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 0.71 g of potassium hydroxide added, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 13

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 1.78 9 of sodium acetate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 14

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 6.6 g of sodium stearate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 15

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 2.41 g of sodium lactate, and the mixture was dissolvedby heating at 100° C. for 30 minutes.

Preparative Example 16

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 1.87 g of trisodium citrate, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Preparative Example 17

Into a 200-ml glass flask was put 100 g of ethylene glycol, and to theflask was added 3.67 g of sodium glutamate, and the mixture wasdissolved by heating at 100° C. for 30 minutes.

Example 3

Production of Polyester

Polycondensation reaction for the low molecular condensate obtained inExample 1 was conducted with the titanium-containing solution preparedin Reference Examples 5, 12, 15, 21, 23, 25 and 26 and with the ethyleneglycol solution of alkali metal or alkali metal compound in theundissolved solid state prepared in Preparative Examples 11 to 17, as apolycondensation catalyst in the combination as shown in Table 3.

Regarding the amount of each catalyst, the titanium-containing solutionprepared in Reference Examples 5, 12, 15, 21, 23, 25 and 26 was added inan amount of 18 ppm in terms of converted titanium atom, relative to theproduced polyethylene terephthalate, and further the ethylene glycolsolution of alkali metal or alkali metal compound in the undissolvedsolid state prepared in Preparative Examples 11 to 17, was added in anamount of 9 ppm in terms of converted sodium, and 15 ppm in terms ofconverted potassium to the produced polyethylene terephthalate, andfurther phosphoric acid was added in an amount of 6 ppm in terms ofconverted phosphorus atom, relative to the produced polyethyleneterephthalate. The time required for obtaining polyethyleneterephthalate which is a liquid polymer product, the solidpolycondensation time (T), the acetaldehyde content in the solid phasepolymerization product and the preform, and the stability parameter(ΔAA) were measured in the same manner as in Example 1.

Table 3 indicates the liquid polycondensation time, the solidpolycondensation time, and the values of M, HM, V_(ssp), [AA]₀, [AA]₁and ΔAA in Example 3.

TABLE 3 Liquid Solid Catalyst Used Polycondensation Polycondensation MHM V_(ssp) [AA]₀ [AA]₁ ΔAA Ti Alkali Metal Time (h) Time (h) (ppm) (ppm)(dl/g · h) (ppm) (ppm) (ppm) Example 3 Reference Preparative Example 111.6 7.8 45 0 0.0256 1.0 5.9 4.9 Example 5 Reference 1.4 7.3 45 0 0.02741.1 6.2 5.1 Example 12 Reference 1.6 7.7 45 0 0.0260 1.0 6.0 5.0 Example15 Reference 1.6 7.6 45 0 0.0263 1.1 6.0 4.9 Example 21 Reference 1.67.7 45 0 0.0260 1.2 6.1 4.9 Example 23 Reference 1.3 7.2 36 0 0.0278 1.26.3 5.1 Example 25 Reference 1.3 7.1 36 0 0.0282 1.1 6.2 5.1 Example 26Reference Preparative Example 12 1.4 7.2 42 0 0.0278 1.0 6.2 5.2 Example25 Preparative Example 13 1.5 7.6 36 0 0.0263 1.3 6.4 5.1 PreparativeExample 14 1.4 7.3 36 0 0.0274 1.1 6.3 5.2 Preparative Example 15 1.47.2 36 0 0.0278 1.0 6.2 5.2 Preparative Example 16 1.3 7.1 36 0 0.02821.1 6.4 5.3 Preparative Example 17 1.4 7.3 36 0 0.0274 1.1 6.3 5.2 NaAcetate 1.5 7.5 36 0 0.0267 1.0 6.4 5.4 Na Stearate 1.4 7.2 36 0 0.02781.1 6.3 5.2 Tri-Na Citrate 1.3 7.1 36 0 0.0282 1.2 6.3 5.1 Na Glutamate1.4 7.5 36 0 0.0267 1.1 6.4 5.3

Reference Example 27

Into a 1,000-ml glass beaker was put 500 ml of deionized water, thebeaker was cooled in an ice bath, and 5 g of titanium tetrachloride wasadded dropwise with stirring. When hydrochloride stopped to occur, thesolution was taken out of the ice bath, 25% ammonia water was addeddropwise at room temperature with stirring, and the pH of the solutionwas adjusted to 9. To this solution was added dropwise 15% aqueousacetate solution at room temperature with stirring, and the pH of thesolution was adjusted to 5. The produced precipitate was isolated byfiltration. The precipitate after washing was maintained as a slurry of2.0% by weight slurry concentration with ethylene glycol-containingaqueous solution of 30% by weight sodium hydroxide (1.0% by weight interms of converted Na) which was prepared separately, for 30 minutes,and granulating and drying were carried out using a spray drier of dualfluid nozzle type at a temperature of 90° C., to give a solidhydrolysate (a solid titanium-containing compound).

Particle size distribution of the obtained solid titanium-containingcompound was 0.5 to 20 μm, and the mean particle diameter was 1.8 μm.

The metal titanium content in the solid titanium-containing compound asmeasured in the same manner as in Reference Example 1 was 26.2% byweight, and the metal sodium content was 25.9% by weight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid titanium-containing compound in ethyleneglycol was more than 15,000 ppm, the carbon content was 9.7% by weight,and the weight ratio of titanium and carbon (Ti/C) was 2.7.

Then, into a 300-ml glass flask were put 170 g of ethylene glycol and 30g of glycerin, and to the flask was added 7.63 g of the solidtitanium-containing compound, and the mixture was dissolved by heatingat 120° C. for 30 minutes, to give a titanium-containing solution. Thetitanium content in the titanium-containing solution as measured by ICPanalysis was 1.0% by weight, the sodium content was 0.99% by weight, andHAZE value as measured in the same manner as in Reference Example 1 was1.4%.

Reference Example 28

The same procedures were conducted as in Reference Example 27 exceptthat the concentration of ethylene glycol-containing aqueous solution of30% by weight sodium hydroxide was 0.5% by weight in terms of convertedNa, to give a titanium-containing solution which is a catalyst forpolyester production.

Particle size distribution of the obtained solid titanium-containingcompound was 0.5 to 20 μm, and the mean particle diameter was 1.7 μm.

The metal titanium content in the solid titanium-containing compound asmeasured in the same manner as in Reference Example 1 was 30.1% byweight, and the metal sodium content was 14.9% by weight.

The fact that the solid titanium-containing compound contains titanium,oxygen, carbon and hydrogen and has Ti—O—C bond, was confirmed byelement analysis, EXAFS analysis and ¹³C-NMR analysis. In addition, themaximum solubility of the solid titanium-containing compound in ethyleneglycol was 15,000 ppm, the carbon content was 10.3% by weight, and theweight ratio of titanium and carbon (Ti/C) was 2.9.

Then, into a 300-ml glass flask were put 170 g of ethylene glycol and 30g of glycerin, and to the flask was added 6.64 g of the solidtitanium-containing compound, and the mixture was dissolved by heatingat 120° C. for 30 minutes, to give a titanium-containing solution. Thetitanium content in the titanium-containing solution as measured by ICPanalysis was 0.98% by weight, the sodium content was 0.49% by weight,and HAZE value as measured in the same manner as in Reference Example 1was 1.5%.

Example 4

Production of Polyester

Polycondensation reaction for the low molecular condensate obtained inExample 1 was conducted with the titanium-containing solution preparedin Reference Examples 27 and 28 and with the ethylene glycol solution ofalkali metal or alkali metal compound in the undissolved solid stateprepared in Preparative Examples 11 to 17, as a polycondensationcatalyst in the combination as shown in Table 3.

Regarding the amount of each catalyst, the titanium-containing solutionprepared in Reference Examples 27 and 28 was added in an amount of 18ppm in terms of converted titanium atom, relative to the producedpolyethylene terephthalate, and further the ethylene glycol solution ofalkali metal compound or alkali metal compound in the undissolved solidstate prepared in Preparative Examples 11 to 17, was added in an amountof 9 ppm of sodium, and 15 ppm of potassium in terms of converted alkalimetal, relative to the produced polyethylene terephthalate, and furtherphosphoric acid was added in an amount of 6 ppm in terms-of convertedphosphorus atom, relative to the produced polyethylene terephthalate.The time required for obtaining polyethylene terephthalate which is aliquid polymer product, the solid polycondensation time (T), theacetaldehyde content in the solid phase polymerization product and thepreform, and the stability parameter (ΔAA) were measured in the samemanner as in Example 1.

Table 4 indicates the liquid polycondensation time, the solidpolycondensation time, and the values of M, HM, V_(ssp), [AA]₀, [AA]₁and ΔAA in Example 4.

TABLE 4 Liquid Solid Catalyst Used Polycondensation Polycondensation MHM V_(ssp) [AA]₀ [AA]₁ ΔAA Ti Alkali Metal Time (h) Time (h) (ppm) (ppm)(dl/g · h) (ppm) (ppm) (ppm) Example 4 Reference — 1.5 7.3 36 0 0.02741.0 6.1 5.1 Example 27 Reference — 1.3 7.1 27 0 0.0282 1.2 6.7 5.5Example 28 Reference Preparative Example 11 1.7 7.9 45 0 0.0253 1.0 5.94.9 Example 27 Reference Preparative Example 11 1.4 7.2 36 0 0.0278 1.16.2 5.1 Example 28 Preparative Example 12 1.4 7.3 42 0 0.0274 1.0 6.25.2 Preparative Example 13 1.5 7.5 36 0 0.0267 1.1 6.3 5.2 PreparativeExample 14 1.3 7.2 36 0 0.0278 1.2 6.2 5.0 Preparative Example 15 1.47.3 36 0 0.0274 1.1 6.3 5.2 Preparative Example 16 1.3 7.2 36 0 0.02781.1 6.4 5.3 Preparative Example 17 1.4 7.3 36 0 0.0274 1.1 6.3 5.2 NaAtetate 1.4 7.4 36 0 0.0270 1.2 6.4 5.2 Na Stearate 1.4 7.3 36 0 0.02741.0 6.3 5.3 Tri-Na Citrate 1.3 7.2 36 0 0.0278 1.1 6.4 5.3 Na Glutamate1.4 7.5 36 0 0.0267 1.1 6.5 5.4

INDUSTRIAL APPLICABILITY

The polyester resin of the present invention has high productivity,stability and safety. By using the catalyst for polyester productionaccording to the present invention as a polycondensation catalyst, apolyester resin can be prepared having high catalytic activity, highstability and low the metal content as compared with the conventionalgermanium compound and antimony compound; and a polyester resin can beobtained having excellent transparency and hue, and low acetaldehydecontent as compared with the case wherein the antimony compound is usedas a polycondensation catalyst.

1. A polyester resin of which the polymerizability parameter satisfiesthe following formula (A-1), the stability parameter satisfies thefollowing formula (B-1), and the metal content parameter furthersatisfies the following formula (C-1):V _(ssp≧)0.025(dl/g·h)  (A-1) wherein V_(ssp) is calculated from theintrinsic viscosity of polyester resin, and the intrinsic viscosity ofpolyester resin after solid polycondensation of this polyester resin at220° C. under nitrogen atmosphere for any hours between 2 hours and 12hours, by the following calculation formula:V _(ssp)=([IV] ₁-[IV] ₀)/T wherein [IV]₀ and [IV]₁ represent intrinsicviscosities (dl/g) before and after the solid polycondensation,respectively, and T represents solid polycondensation time (h);ΔAA≦7.0 (ppm)  (B-1) wherein ΔAA is calculated from the acetaldehydeamount contained originally in the polyester resin, and the acetaldehydeamount contained in a preform obtained by molding this polyester resinwith an injection molding machine at a cylinder temperature of 265 to275° C. for 26±1 seconds of a molding cycle, by the followingcalculation formula:ΔAA=[AA]₁-[AA]₀ wherein [AA]₀ and [AA]₁ represent acetaldehyde contents(ppm by weight) before and after the molding, respectively;M≦50 (ppm)  (C-1) wherein M represents the total amount (ppm by weight)of the metal atoms contained in the polyester resin.
 2. The polyesterresin as described in claim 1, wherein the polycondensation time furthersatisfies the following formula (A-2):T≦8 (h)  (A-2) wherein T represents solid polycondensation time (h)required for elevating the molecular weight of the polyester resin toattain an intrinsic viscosity of 0.84 dl/g by carrying out solidpolycondensation of the polyester resin having an intrinsic viscosity of0.64 dl/g at 220° C. under nitrogen atmosphere.
 3. The polyester resinas described in claim 1 or 2, wherein the metal content parameterfurther satisfies the following formula (C-2):HM≦2 (ppm)  (C-2) wherein HM represents the total amount (ppm by weight)of the heavy metal atoms contained in the polyester resin.
 4. A catalystfor polyester production comprising: (a) a solid titanium-containingcompound which comprises titanium, oxygen, carbon, and hydrogen, whereinsaid solid titanium-containing compound has a Ti—O—C bond, a weightratio of the titanium atom to carbon atom (Ti/C) is in the range of 50to 1, and the maximum solubility in ethylene glycol when dissolved inthe ethylene glycol at 150° C. is 1,000 ppm or more in terms ofconverted titanium atom, and (b) an alkali metal compound, wherein themolar ratio of the alkali metal atoms to the titanium atom in thecatalyst being in the range of 20/1 to 0.1/1.
 5. The catalyst forpolyester production as described in claim 4, wherein the solidtitanium-containing compound (a) further contains alkali metal inaddition to titanium, oxygen, carbon and hydrogen.
 6. A catalyst forpolyester production comprising: a solid titanium-containing compoundwhich comprises titanium, oxygen, carbon, hydrogen, and alkali metal,wherein said solid titanium-containing compound has a Ti—O—C bond, aweight ratio of the titanium atom to carbon atom (Ti/C) is in the rangeof 50 to 1, and the maximum solubility in ethylene glycol when dissolvedin the ethylene glycol under heating at 150° C. is 1,000 ppm or more interms of converted titanium atom, and the molar ratio of the alkalimetal atoms to the titanium atom being in the range of 20/1 to 0.1/1. 7.The catalyst for polyester production as described in any one of claims4 to 6, wherein the titanium atom content in the solidtitanium-containing compound (a) is 5 to 50% by weight and the carbonatom content is 1 to 35% by weight.
 8. The catalyst for polyesterproduction as described in claim 4 or 6, wherein the solidtitanium-containing compound (a) contains at least one kind of elementselected from the group consisting of beryllium, magnesium, calcium,strontium, barium, scandium, yttrium, lanthanum, zirconium, hafnium,vanadium, niobium, tantalum, chrome, molybdenum, tungsten, manganese,iron, ruthenium, cobalt, rhodium, nickel, palladium, copper, zinc,boron, aluminum, gallium, silicon, germanium, tin, antimony andphosphorus in addition to titanium, oxygen, carbon, hydrogen and alkalimetal.
 9. The catalyst for polyester production as described in claim 4or 6 wherein the solid titanium-containing compound (a) is a product ofcontact between hydrolysate of titanium halide or hydrolysate oftitanium alkoxide, and polyol.
 10. A catalyst for polyester productioncomprising (I) the catalyst for polyester production as described inclaim 4 or 6, and (II) a compound of at least one kind of elementselected from the group consisting of beryllium, magnesium, calcium,strontium, barium, boron, aluminum, gallium, manganese, cobalt, zinc,germanium, antimony and phosphorus.
 11. The catalyst for polyesterproduction as described in claim 4 or 6, wherein the solidtitanium-containing compound (a) is a titanium-containing solution inwhich the solid titanium-containing compound (a) is dissolved inethylene glycol-containing solution (c) in an amount of 500 to 100,000ppm in terms of converted titanium atom.
 12. The catalyst for polyesterproduction as described in claim 11, wherein the titanium-containingsolution is obtained by adding the alkali metal compound (b) when thesolid titanium-containing compound (a) is dissolved in the ethyleneglycol-containing solution (c).
 13. The catalyst for polyesterproduction as described in claim 11 wherein the titanium-containingsolution contains a solubilizing aid in the range of 1 to 50% by weightof, relative to the ethylene glycol-containing solution (c).
 14. Thecatalyst for polyester production as described in claim 13 wherein thesolubilizing aid is glycerin or trimethylol propane.
 15. The catalystfor polyester production as described in claim 13 wherein the watercontent of the titanium-containing solution is in the range of 0.05 to15.0% by weight.
 16. The catalyst for polyester production as describedin claim 4 or 6 substantially comprising no antimony compound andgermanium compound.
 17. A method for producing a polyester resin whereinaromatic dicarboxylic acid or an ester-forming derivative thereof andaliphatic diol or an ester-forming derivative thereof are subjected topolycondensation to produce the polyester resin under presence of thecatalyst for polyester production as described in claim 4 or
 6. 18. Apolyester resin prepared by polycondensation of aromatic dicarboxylicacid or an ester-forming derivative thereof and aliphatic diol or anester-forming derivative thereof under presence of the catalyst forpolyester production as described in claim 4 or
 6. 19. A polyester resinas described in claim 18, made by solid polycondensation having anintrinsic viscosity of 0.60 dl/g or more.
 20. A hollow molded containercomprising the polyester resin as described in claim 18.